Fix Select subquery with DollarPlaceholder (#298)

Fixes #286

case.go

@@ -27,7 +27,7 @@ func (b *sqlizerBuffer) WriteSql(item Sqlizer) {
 
 	var str string
 	var args []interface{}
-	str, args, b.err = item.ToSql()
+	str, args, b.err = nestedToSql(item)
 
 	if b.err != nil {
 		return

part.go

@@ -29,9 +29,17 @@ func (p part) ToSql() (sql string, args []interface{}, err error) {
 	return
 }
 
+func nestedToSql(s Sqlizer) (string, []interface{}, error) {
+	if raw, ok := s.(rawSqlizer); ok {
+		return raw.toSqlRaw()
+	} else {
+		return s.ToSql()
+	}
+}
+
 func appendToSql(parts []Sqlizer, w io.Writer, sep string, args []interface{}) ([]interface{}, error) {
 	for i, p := range parts {
-		partSql, partArgs, err := p.ToSql()
+		partSql, partArgs, err := nestedToSql(p)
 		if err != nil {
 			return nil, err
 		} else if len(partSql) == 0 {

select.go

@@ -52,7 +52,7 @@ func (d *selectData) QueryRow() RowScanner {
 }
 
 func (d *selectData) ToSql() (sqlStr string, args []interface{}, err error) {
-	sqlStr, args, err = d.toSql()
+	sqlStr, args, err = d.toSqlRaw()
 	if err != nil {
 		return
 	}
@@ -62,10 +62,6 @@ func (d *selectData) ToSql() (sqlStr string, args []interface{}, err error) {
 }
 
 func (d *selectData) toSqlRaw() (sqlStr string, args []interface{}, err error) {
-	return d.toSql()
-}
-
-func (d *selectData) toSql() (sqlStr string, args []interface{}, err error) {
 	if len(d.Columns) == 0 {
 		err = fmt.Errorf("select statements must have at least one result column")
 		return
@@ -222,6 +218,11 @@ func (b SelectBuilder) ToSql() (string, []interface{}, error) {
 	return data.ToSql()
 }
 
+func (b SelectBuilder) toSqlRaw() (string, []interface{}, error) {
+	data := builder.GetStruct(b).(selectData)
+	return data.toSqlRaw()
+}
+
 // MustSql builds the query into a SQL string and bound args.
 // It panics if there are any errors.
 func (b SelectBuilder) MustSql() (string, []interface{}) {
@@ -232,11 +233,6 @@ func (b SelectBuilder) MustSql() (string, []interface{}) {
 	return sql, args
 }
 
-func (b SelectBuilder) toSqlRaw() (string, []interface{}, error) {
-	data := builder.GetStruct(b).(selectData)
-	return data.toSqlRaw()
-}
-
 // Prefix adds an expression to the beginning of the query
 func (b SelectBuilder) Prefix(sql string, args ...interface{}) SelectBuilder {
 	return b.PrefixExpr(Expr(sql, args...))

select_test.go

@@ -247,6 +247,23 @@ func TestSelectWithEmptyStringWhereClause(t *testing.T) {
 	assert.Equal(t, "SELECT * FROM users", sql)
 }
 
+func TestSelectSubqueryPlaceholderNumbering(t *testing.T) {
+	subquery := Select("a").Where("b = ?", 1).PlaceholderFormat(Dollar)
+	with := subquery.Prefix("WITH a AS (").Suffix(")")
+
+	sql, args, err := Select("*").
+		PrefixExpr(with).
+		FromSelect(subquery, "q").
+		Where("c = ?", 2).
+		PlaceholderFormat(Dollar).
+		ToSql()
+	assert.NoError(t, err)
+
+	expectedSql := "WITH a AS ( SELECT a WHERE b = $1 ) SELECT * FROM (SELECT a WHERE b = $2) AS q WHERE c = $3"
+	assert.Equal(t, expectedSql, sql)
+	assert.Equal(t, []interface{}{1, 1, 2}, args)
+}
+
 func ExampleSelect() {
 	Select("id", "created", "first_name").From("users") // ... continue building up your query