better description.

malloydata · Oct 6, 2023 · ec9a3e6 · ec9a3e6
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Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/patterns/unnest_data.malloynb b/patterns/unnest_data.malloynb
@@ -1,6 +1,10 @@
 >>>markdown
 # Unnesting Data
-Malloy can naturally read unnested data.  Currently there is no mechanism to join something that unnest so for now you have to do it in SQL
+Malloy can naturally read array data when it is in a source.  Currently there is no mechanism to join an array in the Malloy language so we can drop into to SQL to do this.
+
+In the source below we add a column that is based on the `SPLIT` function that returns an array.  When Malloy looks at the SQL for this query, it sees an array and adds as a nested join.  In this case we are looking at the words that appear in the 'CITY' column.  
+
+SQL is optimized so if this column isn't used in a subsequent query, it is not computed.
 >>>malloy
 source: airports is duckdb.sql("""
   SELECT