Allow to use Valuer with Eq expression, #3899

clause/expression.go

@@ -301,6 +301,10 @@ func (like Like) NegationBuild(builder Builder) {
 }
 
 func eqNil(value interface{}) bool {
+	if valuer, ok := value.(driver.Valuer); ok {
+		value, _ = valuer.Value()
+	}
+
 	return value == nil || eqNilReflect(value)
 }
 

clause/expression_test.go

@@ -105,28 +105,29 @@ func TestNamedExpr(t *testing.T) {
 func TestExpression(t *testing.T) {
 	column := "column-name"
 	results := []struct {
-		Expressions    []clause.Expression
+		Expressions []clause.Expression
-		Result string
+		Result      string
 	}{{
 		Expressions: []clause.Expression{
 			clause.Eq{Column: column, Value: "column-value"},
 		},
 		Result: "`column-name` = ?",
-	},{
+	}, {
 		Expressions: []clause.Expression{
 			clause.Eq{Column: column, Value: nil},
 			clause.Eq{Column: column, Value: (*string)(nil)},
 			clause.Eq{Column: column, Value: (*int)(nil)},
 			clause.Eq{Column: column, Value: (*bool)(nil)},
 			clause.Eq{Column: column, Value: (interface{})(nil)},
+			clause.Eq{Column: column, Value: sql.NullString{String: "", Valid: false}},
 		},
 		Result: "`column-name` IS NULL",
-	},{
+	}, {
 		Expressions: []clause.Expression{
 			clause.Neq{Column: column, Value: "column-value"},
 		},
 		Result: "`column-name` <> ?",
-	},{
+	}, {
 		Expressions: []clause.Expression{
 			clause.Neq{Column: column, Value: nil},
 			clause.Neq{Column: column, Value: (*string)(nil)},