Select statement has invalid NULL check syntax when using implicit ni…

…l value #272

exp/bool.go

@@ -3,6 +3,8 @@ package exp
 import (
 	"reflect"
 	"regexp"
+
+	"github.com/doug-martin/goqu/v9/internal/util"
 )
 
 type boolean struct {
@@ -155,7 +157,7 @@ func checkLikeExp(op BooleanOperation, lhs Expression, val interface{}, invert b
 
 // checks a boolean operation normalizing the operation based on the RHS (e.g. "a" = true vs "a" IS TRUE
 func checkBoolExpType(op BooleanOperation, lhs Expression, rhs interface{}, invert bool) BooleanExpression {
-	if rhs == nil {
+	if rhs == nil || util.IsNil(rhs) {
 		op = IsOp
 	} else {
 		switch reflect.Indirect(reflect.ValueOf(rhs)).Kind() {

expressions_example_test.go

@@ -1008,6 +1008,7 @@ func ExampleOr_withAnd() {
 }
 
 func ExampleOr_withExMap() {
+	var val *int
 	ds := goqu.From("test").Where(
 		goqu.Or(
 			// Ex will be anded together
@@ -1018,6 +1019,7 @@ func ExampleOr_withExMap() {
 			goqu.Ex{
 				"col3": nil,
 				"col4": "foo",
+				"col5": val,
 			},
 		),
 	)
@@ -1028,8 +1030,8 @@ func ExampleOr_withExMap() {
 	fmt.Println(sql, args)
 
 	// Output:
-	// SELECT * FROM "test" WHERE ((("col1" = 1) AND ("col2" IS TRUE)) OR (("col3" IS NULL) AND ("col4" = 'foo'))) []
-	// SELECT * FROM "test" WHERE ((("col1" = ?) AND ("col2" IS TRUE)) OR (("col3" IS NULL) AND ("col4" = ?))) [1 foo]
+	// SELECT * FROM "test" WHERE ((("col1" = 1) AND ("col2" IS TRUE)) OR (("col3" IS NULL) AND ("col4" = 'foo') AND ("col5" IS NULL))) []
+	// SELECT * FROM "test" WHERE ((("col1" = ?) AND ("col2" IS TRUE)) OR (("col3" IS NULL) AND ("col4" = ?) AND ("col5" IS NULL))) [1 foo]
 }
 
 func ExampleRange_numbers() {

internal/util/reflect.go

@@ -83,6 +83,18 @@ func IsEmptyValue(v reflect.Value) bool {
 	}
 }
 
+func IsNil(i interface{}) bool {
+	if i == nil {
+		return true
+	}
+	switch reflect.TypeOf(i).Kind() {
+	case reflect.Ptr, reflect.Map, reflect.Array, reflect.Chan, reflect.Slice:
+		return reflect.ValueOf(i).IsNil()
+	default:
+		return false
+	}
+}
+
 var (
 	structMapCache     = make(map[interface{}]ColumnMap)
 	structMapCacheLock = sync.Mutex{}

sqlgen/expression_sql_generator.go

@@ -405,13 +405,15 @@ func (esg *expressionSQLGenerator) booleanExpressionSQL(b sb.SQLBuilder, operato
 
 	if (operatorOp == exp.IsOp || operatorOp == exp.IsNotOp) && esg.dialectOptions.UseLiteralIsBools {
 		// these values must be interpolated because preparing them generates invalid SQL
-		switch rhs {
-		case true:
-			rhs = TrueLiteral
-		case false:
-			rhs = FalseLiteral
-		case nil:
+		if util.IsNil(rhs) {
 			rhs = exp.NewLiteralExpression(string(esg.dialectOptions.Null))
+		} else {
+			switch rhs {
+			case true:
+				rhs = TrueLiteral
+			case false:
+				rhs = FalseLiteral
+			}
 		}
 	}
 	b.WriteRunes(esg.dialectOptions.SpaceRune)