diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3fabbf50..732ae3f5 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,7 +13,7 @@ jobs:
           - elixir: 1.15.6
             otp: 24.3.4.13
           - elixir: 1.15.6
-            otp: 25.3.2.6
+            otp: 26.1.2
             lint: lint
     steps:
       - name: Checkout
diff --git a/lib/ecto/adapters/myxql/connection.ex b/lib/ecto/adapters/myxql/connection.ex
index 55087514..b5cc5bff 100644
--- a/lib/ecto/adapters/myxql/connection.ex
+++ b/lib/ecto/adapters/myxql/connection.ex
@@ -192,7 +192,7 @@ if Code.ensure_loaded?(MyXQL) do
     defp on_conflict({fields, _, []}, _header) when is_list(fields) do
       [
         " ON DUPLICATE KEY UPDATE "
-        | intersperse_map(fields, ?,, fn field ->
+        | Enum.map_intersperse(fields, ?,, fn field ->
             quoted = quote_name(field)
             [quoted, " = VALUES(", quoted, ?)]
           end)
@@ -213,8 +213,8 @@ if Code.ensure_loaded?(MyXQL) do
     defp insert_all(rows) when is_list(rows) do
       [
         "VALUES ",
-        intersperse_map(rows, ?,, fn row ->
-          [?(, intersperse_map(row, ?,, &insert_all_value/1), ?)]
+        Enum.map_intersperse(rows, ?,, fn row ->
+          [?(, Enum.map_intersperse(row, ?,, &insert_all_value/1), ?)]
         end)
       ]
     end
@@ -229,10 +229,10 @@ if Code.ensure_loaded?(MyXQL) do
 
     @impl true
     def update(prefix, table, fields, filters, _returning) do
-      fields = intersperse_map(fields, ", ", &[quote_name(&1), " = ?"])
+      fields = Enum.map_intersperse(fields, ", ", &[quote_name(&1), " = ?"])
 
       filters =
-        intersperse_map(filters, " AND ", fn
+        Enum.map_intersperse(filters, " AND ", fn
           {field, nil} ->
             [quote_name(field), " IS NULL"]
 
@@ -246,7 +246,7 @@ if Code.ensure_loaded?(MyXQL) do
     @impl true
     def delete(prefix, table, filters, _returning) do
       filters =
-        intersperse_map(filters, " AND ", fn
+        Enum.map_intersperse(filters, " AND ", fn
           {field, nil} ->
             [quote_name(field), " IS NULL"]
 
@@ -330,7 +330,7 @@ if Code.ensure_loaded?(MyXQL) do
       do: "TRUE"
 
     defp select(fields, sources, query) do
-      intersperse_map(fields, ", ", fn
+      Enum.map_intersperse(fields, ", ", fn
         {:&, _, [idx]} ->
           case elem(sources, idx) do
             {nil, source, nil} ->
@@ -367,7 +367,7 @@ if Code.ensure_loaded?(MyXQL) do
     defp cte(%{with_ctes: %WithExpr{queries: [_ | _]}} = query, sources) do
       %{with_ctes: with} = query
       recursive_opt = if with.recursive, do: "RECURSIVE ", else: ""
-      ctes = intersperse_map(with.queries, ", ", &cte_expr(&1, sources, query))
+      ctes = Enum.map_intersperse(with.queries, ", ", &cte_expr(&1, sources, query))
       ["WITH ", recursive_opt, ctes, " "]
     end
 
@@ -442,7 +442,7 @@ if Code.ensure_loaded?(MyXQL) do
 
     defp using_join(%{joins: joins} = query, kind, sources) do
       froms =
-        intersperse_map(joins, ", ", fn
+        Enum.map_intersperse(joins, ", ", fn
           %JoinExpr{source: %Ecto.SubQuery{params: [_ | _]}} ->
             error!(
               query,
@@ -511,8 +511,8 @@ if Code.ensure_loaded?(MyXQL) do
     defp group_by(%{group_bys: group_bys} = query, sources) do
       [
         " GROUP BY "
-        | intersperse_map(group_bys, ", ", fn %QueryExpr{expr: expr} ->
-            intersperse_map(expr, ", ", &expr(&1, sources, query))
+        | Enum.map_intersperse(group_bys, ", ", fn %QueryExpr{expr: expr} ->
+            Enum.map_intersperse(expr, ", ", &expr(&1, sources, query))
           end)
       ]
     end
@@ -522,22 +522,22 @@ if Code.ensure_loaded?(MyXQL) do
     defp window(%{windows: windows} = query, sources) do
       [
         " WINDOW "
-        | intersperse_map(windows, ", ", fn {name, %{expr: kw}} ->
+        | Enum.map_intersperse(windows, ", ", fn {name, %{expr: kw}} ->
             [quote_name(name), " AS " | window_exprs(kw, sources, query)]
           end)
       ]
     end
 
     defp window_exprs(kw, sources, query) do
-      [?(, intersperse_map(kw, ?\s, &window_expr(&1, sources, query)), ?)]
+      [?(, Enum.map_intersperse(kw, ?\s, &window_expr(&1, sources, query)), ?)]
     end
 
     defp window_expr({:partition_by, fields}, sources, query) do
-      ["PARTITION BY " | intersperse_map(fields, ", ", &expr(&1, sources, query))]
+      ["PARTITION BY " | Enum.map_intersperse(fields, ", ", &expr(&1, sources, query))]
     end
 
     defp window_expr({:order_by, fields}, sources, query) do
-      ["ORDER BY " | intersperse_map(fields, ", ", &order_by_expr(&1, sources, query))]
+      ["ORDER BY " | Enum.map_intersperse(fields, ", ", &order_by_expr(&1, sources, query))]
     end
 
     defp window_expr({:frame, {:fragment, _, _} = fragment}, sources, query) do
@@ -549,8 +549,8 @@ if Code.ensure_loaded?(MyXQL) do
     defp order_by(%{order_bys: order_bys} = query, sources) do
       [
         " ORDER BY "
-        | intersperse_map(order_bys, ", ", fn %QueryExpr{expr: expr} ->
-            intersperse_map(expr, ", ", &order_by_expr(&1, sources, query))
+        | Enum.map_intersperse(order_bys, ", ", fn %QueryExpr{expr: expr} ->
+            Enum.map_intersperse(expr, ", ", &order_by_expr(&1, sources, query))
           end)
       ]
     end
@@ -654,7 +654,7 @@ if Code.ensure_loaded?(MyXQL) do
     end
 
     defp expr({:in, _, [left, right]}, sources, query) when is_list(right) do
-      args = intersperse_map(right, ?,, &expr(&1, sources, query))
+      args = Enum.map_intersperse(right, ?,, &expr(&1, sources, query))
       [expr(left, sources, query), " IN (", args, ?)]
     end
 
@@ -759,7 +759,7 @@ if Code.ensure_loaded?(MyXQL) do
     end
 
     defp expr({:{}, _, elems}, sources, query) do
-      [?(, intersperse_map(elems, ?,, &expr(&1, sources, query)), ?)]
+      [?(, Enum.map_intersperse(elems, ?,, &expr(&1, sources, query)), ?)]
     end
 
     defp expr({:count, _, []}, _sources, _query), do: "count(*)"
@@ -790,7 +790,7 @@ if Code.ensure_loaded?(MyXQL) do
           [op_to_binary(left, sources, query), op | op_to_binary(right, sources, query)]
 
         {:fun, fun} ->
-          [fun, ?(, modifier, intersperse_map(args, ", ", &expr(&1, sources, query)), ?)]
+          [fun, ?(, modifier, Enum.map_intersperse(args, ", ", &expr(&1, sources, query)), ?)]
       end
     end
 
@@ -847,14 +847,14 @@ if Code.ensure_loaded?(MyXQL) do
 
       [
         "VALUES ",
-        intersperse_map(rows, ?,, fn _ ->
+        Enum.map_intersperse(rows, ?,, fn _ ->
           ["ROW(", values_expr(types, query), ?)]
         end)
       ]
     end
 
     defp values_expr(types, query) do
-      intersperse_map(types, ?,, fn {_field, type} ->
+      Enum.map_intersperse(types, ?,, fn {_field, type} ->
         ["CAST(", ??, " AS ", ecto_cast_to_db(type, query), ?)]
       end)
     end
@@ -989,7 +989,7 @@ if Code.ensure_loaded?(MyXQL) do
           quote_table(index.prefix, index.table),
           ?\s,
           ?(,
-          intersperse_map(index.columns, ", ", &index_expr/1),
+          Enum.map_intersperse(index.columns, ", ", &index_expr/1),
           ?),
           if_do(index.using, [" USING ", to_string(index.using)]),
           if_do(index.concurrently, " LOCK=NONE")
@@ -1097,7 +1097,7 @@ if Code.ensure_loaded?(MyXQL) do
     end
 
     defp column_definitions(table, columns) do
-      intersperse_map(columns, ", ", &column_definition(table, &1))
+      Enum.map_intersperse(columns, ", ", &column_definition(table, &1))
     end
 
     defp column_definition(table, {:add, name, %Reference{} = ref, opts}) do
@@ -1115,7 +1115,7 @@ if Code.ensure_loaded?(MyXQL) do
     end
 
     defp column_changes(table, columns) do
-      intersperse_map(columns, ", ", &column_change(table, &1))
+      Enum.map_intersperse(columns, ", ", &column_change(table, &1))
     end
 
     defp column_change(_table, {_command, _name, %Reference{validate: false}, _opts}) do
@@ -1390,7 +1390,7 @@ if Code.ensure_loaded?(MyXQL) do
       [?`, name, ?`]
     end
 
-    defp quote_names(names), do: intersperse_map(names, ?,, &quote_name/1)
+    defp quote_names(names), do: Enum.map_intersperse(names, ?,, &quote_name/1)
 
     defp quote_table(nil, name), do: quote_table(name)
     defp quote_table(prefix, name), do: [quote_table(prefix), ?., quote_table(name)]
@@ -1409,17 +1409,6 @@ if Code.ensure_loaded?(MyXQL) do
     defp format_to_sql(:map), do: "FORMAT=JSON"
     defp format_to_sql(:text), do: "FORMAT=TRADITIONAL"
 
-    defp intersperse_map(list, separator, mapper, acc \\ [])
-
-    defp intersperse_map([], _separator, _mapper, acc),
-      do: acc
-
-    defp intersperse_map([elem], _separator, mapper, acc),
-      do: [acc | mapper.(elem)]
-
-    defp intersperse_map([elem | rest], separator, mapper, acc),
-      do: intersperse_map(rest, separator, mapper, [acc, mapper.(elem), separator])
-
     defp if_do(condition, value) do
       if condition, do: value, else: []
     end
diff --git a/lib/ecto/adapters/postgres/connection.ex b/lib/ecto/adapters/postgres/connection.ex
index aa140a7c..980edd5a 100644
--- a/lib/ecto/adapters/postgres/connection.ex
+++ b/lib/ecto/adapters/postgres/connection.ex
@@ -223,7 +223,7 @@ if Code.ensure_loaded?(Postgrex) do
 
       values =
         if header == [] do
-          [" VALUES " | intersperse_map(rows, ?,, fn _ -> "(DEFAULT)" end)]
+          [" VALUES " | Enum.map_intersperse(rows, ?,, fn _ -> "(DEFAULT)" end)]
         else
           [" (", quote_names(header), ") " | insert_all(rows, counter_offset)]
         end
@@ -276,7 +276,7 @@ if Code.ensure_loaded?(Postgrex) do
     defp replace(fields) do
       [
         "UPDATE SET "
-        | intersperse_map(fields, ?,, fn field ->
+        | Enum.map_intersperse(fields, ?,, fn field ->
             quoted = quote_name(field)
             [quoted, " = ", "EXCLUDED." | quoted]
           end)
@@ -450,7 +450,7 @@ if Code.ensure_loaded?(Postgrex) do
       do: "TRUE"
 
     defp select_fields(fields, sources, query) do
-      intersperse_map(fields, ", ", fn
+      Enum.map_intersperse(fields, ", ", fn
         {:&, _, [idx]} ->
           case elem(sources, idx) do
             {nil, source, nil} ->
@@ -487,7 +487,7 @@ if Code.ensure_loaded?(Postgrex) do
     defp distinct(%QueryExpr{expr: exprs}, sources, query) do
       {[
          " DISTINCT ON (",
-         intersperse_map(exprs, ", ", fn {_, expr} -> expr(expr, sources, query) end),
+         Enum.map_intersperse(exprs, ", ", fn {_, expr} -> expr(expr, sources, query) end),
          ?)
        ], exprs}
     end
@@ -500,7 +500,7 @@ if Code.ensure_loaded?(Postgrex) do
     defp cte(%{with_ctes: %WithExpr{queries: [_ | _]}} = query, sources) do
       %{with_ctes: with} = query
       recursive_opt = if with.recursive, do: "RECURSIVE ", else: ""
-      ctes = intersperse_map(with.queries, ", ", &cte_expr(&1, sources, query))
+      ctes = Enum.map_intersperse(with.queries, ", ", &cte_expr(&1, sources, query))
       ["WITH ", recursive_opt, ctes, " "]
     end
 
@@ -609,7 +609,7 @@ if Code.ensure_loaded?(Postgrex) do
       end
 
       froms =
-        intersperse_map(inner_joins, ", ", fn
+        Enum.map_intersperse(inner_joins, ", ", fn
           %JoinExpr{qual: :inner, ix: ix, source: source} ->
             {join, name} = get_source(query, sources, ix, source)
             [join, " AS " | [name]]
@@ -627,7 +627,7 @@ if Code.ensure_loaded?(Postgrex) do
 
     defp using_join(%{joins: joins} = query, kind, prefix, sources) do
       froms =
-        intersperse_map(joins, ", ", fn
+        Enum.map_intersperse(joins, ", ", fn
           %JoinExpr{qual: :inner, ix: ix, source: source} ->
             {join, name} = get_source(query, sources, ix, source)
             [join, " AS " | name]
@@ -649,7 +649,7 @@ if Code.ensure_loaded?(Postgrex) do
     defp join(%{joins: joins} = query, sources) do
       [
         ?\s
-        | intersperse_map(joins, ?\s, fn
+        | Enum.map_intersperse(joins, ?\s, fn
             %JoinExpr{
               on: %QueryExpr{expr: expr},
               qual: qual,
@@ -700,9 +700,9 @@ if Code.ensure_loaded?(Postgrex) do
     defp group_by(%{group_bys: group_bys} = query, sources) do
       [
         " GROUP BY "
-        | intersperse_map(group_bys, ", ", fn
+        | Enum.map_intersperse(group_bys, ", ", fn
             %QueryExpr{expr: expr} ->
-              intersperse_map(expr, ", ", &expr(&1, sources, query))
+              Enum.map_intersperse(expr, ", ", &expr(&1, sources, query))
           end)
       ]
     end
@@ -712,22 +712,22 @@ if Code.ensure_loaded?(Postgrex) do
     defp window(%{windows: windows} = query, sources) do
       [
         " WINDOW "
-        | intersperse_map(windows, ", ", fn {name, %{expr: kw}} ->
+        | Enum.map_intersperse(windows, ", ", fn {name, %{expr: kw}} ->
             [quote_name(name), " AS " | window_exprs(kw, sources, query)]
           end)
       ]
     end
 
     defp window_exprs(kw, sources, query) do
-      [?(, intersperse_map(kw, ?\s, &window_expr(&1, sources, query)), ?)]
+      [?(, Enum.map_intersperse(kw, ?\s, &window_expr(&1, sources, query)), ?)]
     end
 
     defp window_expr({:partition_by, fields}, sources, query) do
-      ["PARTITION BY " | intersperse_map(fields, ", ", &expr(&1, sources, query))]
+      ["PARTITION BY " | Enum.map_intersperse(fields, ", ", &expr(&1, sources, query))]
     end
 
     defp window_expr({:order_by, fields}, sources, query) do
-      ["ORDER BY " | intersperse_map(fields, ", ", &order_by_expr(&1, sources, query))]
+      ["ORDER BY " | Enum.map_intersperse(fields, ", ", &order_by_expr(&1, sources, query))]
     end
 
     defp window_expr({:frame, {:fragment, _, _} = fragment}, sources, query) do
@@ -739,7 +739,7 @@ if Code.ensure_loaded?(Postgrex) do
     defp order_by(%{order_bys: order_bys} = query, distinct, sources) do
       order_bys = Enum.flat_map(order_bys, & &1.expr)
       order_bys = order_by_concat(distinct, order_bys)
-      [" ORDER BY " | intersperse_map(order_bys, ", ", &order_by_expr(&1, sources, query))]
+      [" ORDER BY " | Enum.map_intersperse(order_bys, ", ", &order_by_expr(&1, sources, query))]
     end
 
     defp order_by_concat([head | left], [head | right]), do: [head | order_by_concat(left, right)]
@@ -852,7 +852,7 @@ if Code.ensure_loaded?(Postgrex) do
     end
 
     defp expr({:in, _, [left, right]}, sources, query) when is_list(right) do
-      args = intersperse_map(right, ?,, &expr(&1, sources, query))
+      args = Enum.map_intersperse(right, ?,, &expr(&1, sources, query))
       [expr(left, sources, query), " IN (", args, ?)]
     end
 
@@ -954,7 +954,7 @@ if Code.ensure_loaded?(Postgrex) do
     end
 
     defp expr({:{}, _, elems}, sources, query) do
-      [?(, intersperse_map(elems, ?,, &expr(&1, sources, query)), ?)]
+      [?(, Enum.map_intersperse(elems, ?,, &expr(&1, sources, query)), ?)]
     end
 
     defp expr({:count, _, []}, _sources, _query), do: "count(*)"
@@ -984,7 +984,7 @@ if Code.ensure_loaded?(Postgrex) do
           [maybe_paren(left, sources, query), op | maybe_paren(right, sources, query)]
 
         {:fun, fun} ->
-          [fun, ?(, modifier, intersperse_map(args, ", ", &expr(&1, sources, query)), ?)]
+          [fun, ?(, modifier, Enum.map_intersperse(args, ", ", &expr(&1, sources, query)), ?)]
       end
     end
 
@@ -1003,7 +1003,7 @@ if Code.ensure_loaded?(Postgrex) do
     end
 
     defp expr(list, sources, query) when is_list(list) do
-      ["ARRAY[", intersperse_map(list, ?,, &expr(&1, sources, query)), ?]]
+      ["ARRAY[", Enum.map_intersperse(list, ?,, &expr(&1, sources, query)), ?]]
     end
 
     defp expr(%Decimal{} = decimal, _sources, _query) do
@@ -1044,7 +1044,7 @@ if Code.ensure_loaded?(Postgrex) do
     end
 
     defp json_extract_path(expr, path, sources, query) do
-      path = intersperse_map(path, ?,, &escape_json/1)
+      path = Enum.map_intersperse(path, ?,, &escape_json/1)
       [?(, expr(expr, sources, query), "#>'{", path, "}')"]
     end
 
@@ -1207,8 +1207,8 @@ if Code.ensure_loaded?(Postgrex) do
     end
 
     def execute_ddl({command, %Index{} = index}) when command in @creates do
-      fields = intersperse_map(index.columns, ", ", &index_expr/1)
-      include_fields = intersperse_map(index.include, ", ", &index_expr/1)
+      fields = Enum.map_intersperse(index.columns, ", ", &index_expr/1)
+      include_fields = Enum.map_intersperse(index.include, ", ", &index_expr/1)
 
       maybe_nulls_distinct =
         case index.nulls_distinct do
@@ -1388,7 +1388,7 @@ if Code.ensure_loaded?(Postgrex) do
     end
 
     defp column_definitions(table, columns) do
-      intersperse_map(columns, ", ", &column_definition(table, &1))
+      Enum.map_intersperse(columns, ", ", &column_definition(table, &1))
     end
 
     defp column_definition(table, {:add, name, %Reference{} = ref, opts}) do
@@ -1407,7 +1407,7 @@ if Code.ensure_loaded?(Postgrex) do
     end
 
     defp column_changes(table, columns) do
-      intersperse_map(columns, ", ", &column_change(table, &1))
+      Enum.map_intersperse(columns, ", ", &column_change(table, &1))
     end
 
     defp column_change(table, {:add, name, %Reference{} = ref, opts}) do
@@ -1758,7 +1758,7 @@ if Code.ensure_loaded?(Postgrex) do
     end
 
     defp quote_names(names) do
-      intersperse_map(names, ?,, &quote_name/1)
+      Enum.map_intersperse(names, ?,, &quote_name/1)
     end
 
     defp quote_name(name) when is_atom(name) do
@@ -1799,17 +1799,6 @@ if Code.ensure_loaded?(Postgrex) do
 
     defp single_quote(value), do: [?', escape_string(value), ?']
 
-    defp intersperse_map(list, separator, mapper, acc \\ [])
-
-    defp intersperse_map([], _separator, _mapper, acc),
-      do: acc
-
-    defp intersperse_map([elem], _separator, mapper, acc),
-      do: [acc | mapper.(elem)]
-
-    defp intersperse_map([elem | rest], separator, mapper, acc),
-      do: intersperse_map(rest, separator, mapper, [acc, mapper.(elem), separator])
-
     defp intersperse_reduce(list, separator, user_acc, reducer, acc \\ [])
 
     defp intersperse_reduce([], _separator, user_acc, _reducer, acc),
diff --git a/lib/ecto/adapters/tds/connection.ex b/lib/ecto/adapters/tds/connection.ex
index 842acaac..8ef788d0 100644
--- a/lib/ecto/adapters/tds/connection.ex
+++ b/lib/ecto/adapters/tds/connection.ex
@@ -393,7 +393,7 @@ if Code.ensure_loaded?(Tds) do
     end
 
     defp select(fields, sources, query) do
-      intersperse_map(fields, ", ", fn
+      Enum.map_intersperse(fields, ", ", fn
         {:&, _, [idx]} ->
           case elem(sources, idx) do
             {nil, source, nil} ->
@@ -435,7 +435,7 @@ if Code.ensure_loaded?(Tds) do
     end
 
     defp cte(%{with_ctes: %WithExpr{queries: [_ | _] = queries}} = query, sources) do
-      ctes = intersperse_map(queries, ", ", &cte_expr(&1, sources, query))
+      ctes = Enum.map_intersperse(queries, ", ", &cte_expr(&1, sources, query))
       ["WITH ", ctes, " "]
     end
 
@@ -467,7 +467,7 @@ if Code.ensure_loaded?(Tds) do
     defp cte_header(%Ecto.Query{select: %{fields: fields}} = query, _) do
       [
         " (",
-        intersperse_map(fields, ",", fn
+        Enum.map_intersperse(fields, ",", fn
           {key, _} ->
             quote_name(key)
 
@@ -526,7 +526,7 @@ if Code.ensure_loaded?(Tds) do
     defp join(%{joins: joins} = query, sources) do
       [
         ?\s,
-        intersperse_map(joins, ?\s, fn
+        Enum.map_intersperse(joins, ?\s, fn
           %JoinExpr{on: %QueryExpr{expr: expr}, qual: qual, ix: ix, source: source, hints: hints} ->
             {join, name} = get_source(query, sources, ix, source)
             qual_text = join_qual(qual, query)
@@ -571,8 +571,8 @@ if Code.ensure_loaded?(Tds) do
     defp group_by(%{group_bys: group_bys} = query, sources) do
       [
         " GROUP BY "
-        | intersperse_map(group_bys, ", ", fn %QueryExpr{expr: expr} ->
-            intersperse_map(expr, ", ", &expr(&1, sources, query))
+        | Enum.map_intersperse(group_bys, ", ", fn %QueryExpr{expr: expr} ->
+            Enum.map_intersperse(expr, ", ", &expr(&1, sources, query))
           end)
       ]
     end
@@ -582,8 +582,8 @@ if Code.ensure_loaded?(Tds) do
     defp order_by(%{order_bys: order_bys} = query, sources) do
       [
         " ORDER BY "
-        | intersperse_map(order_bys, ", ", fn %QueryExpr{expr: expr} ->
-            intersperse_map(expr, ", ", &order_by_expr(&1, sources, query))
+        | Enum.map_intersperse(order_bys, ", ", fn %QueryExpr{expr: expr} ->
+            Enum.map_intersperse(expr, ", ", &order_by_expr(&1, sources, query))
           end)
       ]
     end
@@ -860,7 +860,7 @@ if Code.ensure_loaded?(Tds) do
           [op_to_binary(left, sources, query), op | op_to_binary(right, sources, query)]
 
         {:fun, fun} ->
-          [fun, ?(, modifier, intersperse_map(args, ", ", &expr(&1, sources, query)), ?)]
+          [fun, ?(, modifier, Enum.map_intersperse(args, ", ", &expr(&1, sources, query)), ?)]
       end
     end
 
@@ -995,7 +995,7 @@ if Code.ensure_loaded?(Tds) do
     defp returning([], _verb), do: []
 
     defp returning(returning, verb) when is_list(returning) do
-      [" OUTPUT ", intersperse_map(returning, ", ", &[verb, ?., quote_name(&1)])]
+      [" OUTPUT ", Enum.map_intersperse(returning, ", ", &[verb, ?., quote_name(&1)])]
     end
 
     defp returning(%{select: nil}, _, _),
@@ -1004,7 +1004,7 @@ if Code.ensure_loaded?(Tds) do
     defp returning(%{select: %{fields: fields}} = query, idx, verb),
       do: [
         " OUTPUT "
-        | intersperse_map(fields, ", ", fn
+        | Enum.map_intersperse(fields, ", ", fn
             {{:., _, [{:&, _, [^idx]}, key]}, _, _} -> [verb, ?., quote_name(key)]
             _ -> error!(query, "MSSQL can only return table #{verb} columns")
           end)
@@ -1157,7 +1157,7 @@ if Code.ensure_loaded?(Tds) do
       include =
         index.include
         |> List.wrap()
-        |> intersperse_map(", ", &index_expr/1)
+        |> Enum.map_intersperse(", ", &index_expr/1)
 
       [
         [
@@ -1173,7 +1173,7 @@ if Code.ensure_loaded?(Tds) do
           " ON ",
           quote_table(prefix, index.table),
           " (",
-          intersperse_map(index.columns, ", ", &index_expr/1),
+          Enum.map_intersperse(index.columns, ", ", &index_expr/1),
           ?),
           if_do(include != [], [" INCLUDE ", ?(, include, ?)]),
           if_do(index.where, [" WHERE (", index.where, ?)]),
@@ -1321,7 +1321,7 @@ if Code.ensure_loaded?(Tds) do
     end
 
     defp column_definitions(table, columns) do
-      intersperse_map(columns, ", ", &column_definition(table, &1))
+      Enum.map_intersperse(columns, ", ", &column_definition(table, &1))
     end
 
     defp column_definition(table, {:add, name, %Reference{} = ref, opts}) do
@@ -1628,7 +1628,7 @@ if Code.ensure_loaded?(Tds) do
       "[#{name}]"
     end
 
-    defp quote_names(names), do: intersperse_map(names, ?,, &quote_name/1)
+    defp quote_names(names), do: Enum.map_intersperse(names, ?,, &quote_name/1)
 
     defp quote_table(nil, name), do: quote_table(name)
 
@@ -1681,13 +1681,6 @@ if Code.ensure_loaded?(Tds) do
       name
     end
 
-    defp intersperse_map([], _separator, _mapper), do: []
-    defp intersperse_map([elem], _separator, mapper), do: mapper.(elem)
-
-    defp intersperse_map([elem | rest], separator, mapper) do
-      [mapper.(elem), separator | intersperse_map(rest, separator, mapper)]
-    end
-
     defp intersperse_reduce(list, separator, user_acc, reducer, acc \\ [])
 
     defp intersperse_reduce([], _separator, user_acc, _reducer, acc),
diff --git a/test/ecto/adapters/myxql_test.exs b/test/ecto/adapters/myxql_test.exs
index a9f9f10b..37996bb2 100644
--- a/test/ecto/adapters/myxql_test.exs
+++ b/test/ecto/adapters/myxql_test.exs
@@ -1485,10 +1485,16 @@ defmodule Ecto.Adapters.MyXQLTest do
       |> plan()
       |> all()
 
+    cast_types = %{bid: "binary(16)", num: "unsigned"}
+    from_values_text = values_text(values, cast_types)
+    join_values_text = values_text(values, cast_types)
+    select_fields = Enum.map_join(types, ", ", fn {field, _} -> "v1.`#{field}`" end)
+    field_names = Enum.map_join(types, ",", fn {field, _} -> "`#{field}`" end)
+
     assert query ==
-             ~s{SELECT v1.`bid`, v1.`num` } <>
-               ~s{FROM (VALUES ROW(CAST(? AS binary(16)),CAST(? AS unsigned)),ROW(CAST(? AS binary(16)),CAST(? AS unsigned))) AS v0 (`bid`,`num`) } <>
-               ~s{INNER JOIN (VALUES ROW(CAST(? AS binary(16)),CAST(? AS unsigned)),ROW(CAST(? AS binary(16)),CAST(? AS unsigned))) AS v1 (`bid`,`num`) ON v0.`bid` = v1.`bid` } <>
+             ~s{SELECT #{select_fields} } <>
+               ~s{FROM (#{from_values_text}) AS v0 (#{field_names}) } <>
+               ~s{INNER JOIN (#{join_values_text}) AS v1 (#{field_names}) ON v0.`bid` = v1.`bid` } <>
                ~s{WHERE (v0.`num` = ?)}
   end
 
@@ -1502,9 +1508,13 @@ defmodule Ecto.Adapters.MyXQLTest do
       |> plan(:delete_all)
       |> delete_all()
 
+    cast_types = %{bid: "binary(16)", num: "unsigned"}
+    values_text = values_text(values, cast_types)
+    fields = Enum.map_join(types, ",", fn {field, _} -> "`#{field}`" end)
+
     assert query ==
              ~s{DELETE s0.* FROM `schema` AS s0 } <>
-               ~s{INNER JOIN (VALUES ROW(CAST(? AS binary(16)),CAST(? AS unsigned)),ROW(CAST(? AS binary(16)),CAST(? AS unsigned))) AS v1 (`bid`,`num`) } <>
+               ~s{INNER JOIN (#{values_text}) AS v1 (#{fields}) } <>
                ~s{ON s0.`x` = v1.`num` WHERE (v1.`num` = ?)}
   end
 
@@ -1523,12 +1533,34 @@ defmodule Ecto.Adapters.MyXQLTest do
       |> plan(:update_all)
       |> update_all()
 
+    cast_types = %{bid: "binary(16)", num: "unsigned"}
+    values_text = values_text(values, cast_types)
+    fields = Enum.map_join(types, ",", fn {field, _} -> "`#{field}`" end)
+
     assert query ==
              ~s{UPDATE `schema` AS s0, } <>
-               ~s{(VALUES ROW(CAST(? AS binary(16)),CAST(? AS unsigned)),ROW(CAST(? AS binary(16)),CAST(? AS unsigned))) AS v1 (`bid`,`num`) } <>
+               ~s{(#{values_text}) AS v1 (#{fields}) } <>
                ~s{SET s0.`y` = v1.`num` WHERE (s0.`x` = v1.`num`) AND (v1.`num` = ?)}
   end
 
+  defp values_text(values, types) do
+    types = Map.to_list(types)
+
+    [
+      "VALUES ",
+      Enum.map_intersperse(values, ?,, fn _ ->
+        ["ROW(", values_expr(types), ?)]
+      end)
+    ]
+    |> IO.iodata_to_binary()
+  end
+
+  defp values_expr(types) do
+    Enum.map_intersperse(types, ?,, fn {field, _} ->
+      ["CAST(", ??, " AS ", types[field], ?)]
+    end)
+  end
+
   # DDL
 
   import Ecto.Migration, only: [table: 1, table: 2, index: 2, index: 3, constraint: 3]
@@ -1708,15 +1740,18 @@ defmodule Ecto.Adapters.MyXQLTest do
   end
 
   test "create table with a map column, and a map default with values" do
+    default = %{foo: "bar", baz: "boom"}
+    default_text = "'{" <> Enum.map_join(default, ",", fn {k, v} -> ~s{"#{k}":"#{v}"} end) <> "}'"
+
     create =
       {:create, table(:posts),
        [
-         {:add, :a, :map, [default: %{foo: "bar", baz: "boom"}]}
+         {:add, :a, :map, [default: default]}
        ]}
 
     assert execute_ddl(create) == [
              """
-             CREATE TABLE `posts` (`a` json DEFAULT ('{\"baz\":\"boom\",\"foo\":\"bar\"}')) ENGINE = INNODB
+             CREATE TABLE `posts` (`a` json DEFAULT (#{default_text})) ENGINE = INNODB
              """
              |> remove_newlines
            ]
diff --git a/test/ecto/adapters/postgres_test.exs b/test/ecto/adapters/postgres_test.exs
index 1f5ff2bd..0e15be94 100644
--- a/test/ecto/adapters/postgres_test.exs
+++ b/test/ecto/adapters/postgres_test.exs
@@ -1,7 +1,10 @@
+Code.require_file("../../support/connection_helpers.exs", __DIR__)
+
 defmodule Ecto.Adapters.PostgresTest do
   use ExUnit.Case, async: true
 
   import Ecto.Query
+  import Support.ConnectionHelpers
 
   alias Ecto.Queryable
   alias Ecto.Adapters.Postgres.Connection, as: SQL
@@ -1889,10 +1892,16 @@ defmodule Ecto.Adapters.PostgresTest do
       |> plan()
       |> all()
 
+    cast_types = %{bid: "uuid", num: "bigint"}
+    from_values_text = values_text(values, cast_types, 1)
+    join_values_text = values_text(values, cast_types, 5)
+    select_fields = Enum.map_join(types, ", ", fn {field, _} -> ~s{v1."#{field}"} end)
+    field_names = Enum.map_join(types, ",", fn {field, _} -> ~s{"#{field}"} end)
+
     assert query ==
-             ~s{SELECT v1."bid", v1."num" } <>
-               ~s{FROM (VALUES ($1::uuid,$2::bigint),($3::uuid,$4::bigint)) AS v0 ("bid","num") } <>
-               ~s{INNER JOIN (VALUES ($5::uuid,$6::bigint),($7::uuid,$8::bigint)) AS v1 ("bid","num") ON v0."bid" = v1."bid" } <>
+             ~s{SELECT #{select_fields} } <>
+               ~s{FROM (#{from_values_text}) AS v0 (#{field_names}) } <>
+               ~s{INNER JOIN (#{join_values_text}) AS v1 (#{field_names}) ON v0."bid" = v1."bid" } <>
                ~s{WHERE (v0."num" = $9)}
   end
 
@@ -1906,9 +1915,13 @@ defmodule Ecto.Adapters.PostgresTest do
       |> plan(:delete_all)
       |> delete_all()
 
+    cast_types = %{bid: "uuid", num: "bigint"}
+    values_text = values_text(values, cast_types, 1)
+    fields = Enum.map_join(types, ",", fn {field, _} -> ~s{"#{field}"} end)
+
     assert query ==
              ~s{DELETE FROM "schema" AS s0 } <>
-               ~s{USING (VALUES ($1::uuid,$2::bigint),($3::uuid,$4::bigint)) AS v1 ("bid","num") } <>
+               ~s{USING (#{values_text}) AS v1 (#{fields}) } <>
                ~s{WHERE (s0."x" = v1."num") AND (v1."num" = $5)}
   end
 
@@ -1927,12 +1940,36 @@ defmodule Ecto.Adapters.PostgresTest do
       |> plan(:update_all)
       |> update_all()
 
+    cast_types = %{bid: "uuid", num: "bigint"}
+    values_text = values_text(values, cast_types, 1)
+    fields = Enum.map_join(types, ",", fn {field, _} -> ~s{"#{field}"} end)
+
     assert query ==
              ~s{UPDATE "schema" AS s0 SET "y" = v1."num" } <>
-               ~s{FROM (VALUES ($1::uuid,$2::bigint),($3::uuid,$4::bigint)) AS v1 ("bid","num") } <>
+               ~s{FROM (#{values_text}) AS v1 (#{fields}) } <>
                ~s{WHERE (s0."x" = v1."num") AND (v1."num" = $5)}
   end
 
+  defp values_text(values, types, ix) do
+    types = Map.to_list(types)
+
+    [
+      "VALUES ",
+      intersperse_reduce(values, ?,, ix, fn _, ix ->
+        {value, ix} = values_expr(types, ix)
+        {[?(, value, ?)], ix}
+      end)
+      |> elem(0)
+    ]
+    |> IO.iodata_to_binary()
+  end
+
+  defp values_expr(types, ix) do
+    intersperse_reduce(types, ?,, ix, fn {field, _}, ix ->
+      {[?$, Integer.to_string(ix), ?:, ?: | types[field]], ix + 1}
+    end)
+  end
+
   # DDL
 
   alias Ecto.Migration.Reference
@@ -2231,14 +2268,17 @@ defmodule Ecto.Adapters.PostgresTest do
   end
 
   test "create table with a map column, and a map default with values" do
+    default = %{foo: "bar", baz: "boom"}
+    default_text = "'{" <> Enum.map_join(default, ",", fn {k, v} -> ~s{"#{k}":"#{v}"} end) <> "}'"
+
     create =
       {:create, table(:posts),
        [
-         {:add, :a, :map, [default: %{foo: "bar", baz: "boom"}]}
+         {:add, :a, :map, [default: default]}
        ]}
 
     assert execute_ddl(create) == [
-             ~s|CREATE TABLE "posts" ("a" jsonb DEFAULT '{"baz":"boom","foo":"bar"}')|
+             ~s|CREATE TABLE "posts" ("a" jsonb DEFAULT #{default_text})|
            ]
   end
 
diff --git a/test/ecto/adapters/tds_test.exs b/test/ecto/adapters/tds_test.exs
index 6fd3a7d2..b9e344c6 100644
--- a/test/ecto/adapters/tds_test.exs
+++ b/test/ecto/adapters/tds_test.exs
@@ -1,7 +1,10 @@
+Code.require_file("../../support/connection_helpers.exs", __DIR__)
+
 defmodule Ecto.Adapters.TdsTest do
   use ExUnit.Case, async: true
 
   import Ecto.Query
+  import Support.ConnectionHelpers
 
   alias Ecto.Queryable
   alias Ecto.Adapters.Tds.Connection, as: SQL
@@ -1309,10 +1312,16 @@ defmodule Ecto.Adapters.TdsTest do
       |> plan()
       |> all()
 
+    cast_types = %{bid: "uniqueidentifier", num: "integer"}
+    from_values_text = values_text(values, cast_types, 1)
+    join_values_text = values_text(values, cast_types, 5)
+    select_fields = Enum.map_join(types, ", ", fn {field, _} -> "v1.[#{field}]" end)
+    field_names = Enum.map_join(types, ",", fn {field, _} -> "[#{field}]" end)
+
     assert query ==
-             ~s{SELECT v1.[bid], v1.[num] } <>
-               ~s{FROM (VALUES (CAST(@1 AS uniqueidentifier),CAST(@2 AS integer)),(CAST(@3 AS uniqueidentifier),CAST(@4 AS integer))) AS v0 ([bid],[num]) } <>
-               ~s{INNER JOIN (VALUES (CAST(@5 AS uniqueidentifier),CAST(@6 AS integer)),(CAST(@7 AS uniqueidentifier),CAST(@8 AS integer))) AS v1 ([bid],[num]) ON v0.[bid] = v1.[bid] } <>
+             ~s{SELECT #{select_fields} } <>
+               ~s{FROM (#{from_values_text}) AS v0 (#{field_names}) } <>
+               ~s{INNER JOIN (#{join_values_text}) AS v1 (#{field_names}) ON v0.[bid] = v1.[bid] } <>
                ~s{WHERE (v0.[num] = @9)}
   end
 
@@ -1326,9 +1335,13 @@ defmodule Ecto.Adapters.TdsTest do
       |> plan(:delete_all)
       |> delete_all()
 
+    cast_types = %{bid: "uniqueidentifier", num: "integer"}
+    values_text = values_text(values, cast_types, 1)
+    fields = Enum.map_join(types, ",", fn {field, _} -> "[#{field}]" end)
+
     assert query ==
              ~s{DELETE s0 FROM [schema] AS s0 } <>
-               ~s{INNER JOIN (VALUES (CAST(@1 AS uniqueidentifier),CAST(@2 AS integer)),(CAST(@3 AS uniqueidentifier),CAST(@4 AS integer))) AS v1 ([bid],[num]) } <>
+               ~s{INNER JOIN (#{values_text}) AS v1 (#{fields}) } <>
                ~s{ON s0.[x] = v1.[num] WHERE (v1.[num] = @5)}
   end
 
@@ -1347,12 +1360,36 @@ defmodule Ecto.Adapters.TdsTest do
       |> plan(:update_all)
       |> update_all()
 
+    cast_types = %{bid: "uniqueidentifier", num: "integer"}
+    values_text = values_text(values, cast_types, 1)
+    fields = Enum.map_join(types, ",", fn {field, _} -> "[#{field}]" end)
+
     assert query ==
              ~s{UPDATE s0 SET s0.[y] = v1.[num] FROM [schema] AS s0 } <>
-               ~s{INNER JOIN (VALUES (CAST(@1 AS uniqueidentifier),CAST(@2 AS integer)),(CAST(@3 AS uniqueidentifier),CAST(@4 AS integer))) AS v1 ([bid],[num]) } <>
+               ~s{INNER JOIN (#{values_text}) AS v1 (#{fields}) } <>
                ~s{ON s0.[x] = v1.[num] WHERE (v1.[num] = @5)}
   end
 
+  defp values_text(values, types, ix) do
+    types = Map.to_list(types)
+
+    [
+      "VALUES ",
+      intersperse_reduce(values, ?,, ix, fn _, ix ->
+        {value, ix} = values_expr(types, ix)
+        {[?(, value, ?)], ix}
+      end)
+      |> elem(0)
+    ]
+    |> IO.iodata_to_binary()
+  end
+
+  defp values_expr(types, ix) do
+    intersperse_reduce(types, ?,, ix, fn {field, _}, ix ->
+      {["CAST(", ?@, Integer.to_string(ix), " AS ", types[field], ?)], ix + 1}
+    end)
+  end
+
   ## DDL
 
   import Ecto.Migration,
diff --git a/test/support/connection_helpers.exs b/test/support/connection_helpers.exs
new file mode 100644
index 00000000..9358d624
--- /dev/null
+++ b/test/support/connection_helpers.exs
@@ -0,0 +1,19 @@
+defmodule Support.ConnectionHelpers do
+  @doc """
+  Reduces and intersperses a list in one pass.
+  """
+  def intersperse_reduce(list, separator, user_acc, reducer, acc \\ [])
+
+  def intersperse_reduce([], _separator, user_acc, _reducer, acc),
+    do: {acc, user_acc}
+
+  def intersperse_reduce([elem], _separator, user_acc, reducer, acc) do
+    {elem, user_acc} = reducer.(elem, user_acc)
+    {[acc | elem], user_acc}
+  end
+
+  def intersperse_reduce([elem | rest], separator, user_acc, reducer, acc) do
+    {elem, user_acc} = reducer.(elem, user_acc)
+    intersperse_reduce(rest, separator, user_acc, reducer, [acc, elem, separator])
+  end
+end
diff --git a/test/test_repo.exs b/test/support/test_repo.exs
similarity index 100%
rename from test/test_repo.exs
rename to test/support/test_repo.exs
diff --git a/test/test_helper.exs b/test/test_helper.exs
index 1dc161b7..505fcd9d 100644
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@@ -4,7 +4,7 @@ Mix.shell(Mix.Shell.Process)
 System.put_env("ECTO_EDITOR", "")
 Logger.configure(level: :info)
 
-Code.require_file("test_repo.exs", __DIR__)
+Code.require_file("support/test_repo.exs", __DIR__)
 Code.require_file("../integration_test/support/file_helpers.exs", __DIR__)
 ExUnit.start()