Avoid unnecessary double wrapping of SELECT statement when used as single function parameter.

internal/jet/literal_expression.go

@@ -375,9 +375,14 @@ type wrap struct {
 	expressions []Expression
 }
 
-func (n *wrap) serialize(statement StatementType, out *SQLBuilder, options ...SerializeOption) {
+func (n *wrap) serialize(statementType StatementType, out *SQLBuilder, options ...SerializeOption) {
 	out.WriteString("(")
-	serializeExpressionList(statement, n.expressions, ", ", out)
+
+	if len(n.expressions) == 1 {
+		options = append(options, NoWrap, Ident)
+	}
+	serializeExpressionList(statementType, n.expressions, ", ", out, options...)
+
 	out.WriteString(")")
 }
 

internal/jet/serializer.go

@@ -7,8 +7,10 @@ type SerializeOption int
 const (
 	NoWrap SerializeOption = iota
 	SkipNewLine
+	Ident
 
 	fallTroughOptions // fall trough options
+
 	ShortName
 )
 

internal/jet/statement.go

@@ -195,10 +195,19 @@ func (s *statementImpl) serialize(statement StatementType, out *SQLBuilder, opti
 		out.IncreaseIdent()
 	}
 
+	if contains(options, Ident) {
+		out.IncreaseIdent()
+	}
+
 	for _, clause := range s.Clauses {
 		clause.Serialize(statement, out, FallTrough(options)...)
 	}
 
+	if contains(options, Ident) {
+		out.DecreaseIdent()
+		out.NewLine()
+	}
+
 	if !contains(options, NoWrap) {
 		out.DecreaseIdent()
 		out.NewLine()

internal/jet/utils.go

@@ -21,14 +21,19 @@ func SerializeClauseList(statement StatementType, clauses []Serializer, out *SQL
 	}
 }
 
-func serializeExpressionList(statement StatementType, expressions []Expression, separator string, out *SQLBuilder) {
+func serializeExpressionList(
+	statement StatementType,
+	expressions []Expression,
+	separator string,
+	out *SQLBuilder,
+	options ...SerializeOption) {
 
-	for i, value := range expressions {
+	for i, expression := range expressions {
 		if i > 0 {
 			out.WriteString(separator)
 		}
 
-		value.serialize(statement, out)
+		expression.serialize(statement, out, options...)
 	}
 }