support nested sql

README.md

@@ -3,7 +3,7 @@
 [![Build Status](https://travis-ci.org/huandu/go-sqlbuilder.svg?branch=master)](https://travis-ci.org/huandu/go-sqlbuilder)
 [![GoDoc](https://godoc.org/github.com/huandu/go-sqlbuilder?status.svg)](https://godoc.org/github.com/huandu/go-sqlbuilder)
 
-Package `go-sqlbuilder` provides a set of flexible and powerful SQL string builders. The only goal of this package is to build SQL string with arguments which can be used in `DB#Query` defined in package `database/sql`.
+Package `sqlbuilder` provides a set of flexible and powerful SQL string builders. The only goal of this package is to build SQL string with arguments which can be used in `DB#Query` defined in package `database/sql`.
 
 ## Install ##
 

args.go

@@ -88,8 +88,16 @@ func (args *Args) Compile(sql string) (query string, values []interface{}) {
 				sql = sql[i:]
 
 				if pointer, err := strconv.Atoi(digits); err == nil && pointer < len(args.args) {
-					buf.WriteRune('?')
-					values = append(values, args.args[pointer])
+					arg := args.args[pointer]
+
+					if b, ok := arg.(Builder); ok {
+						sql, nestedArgs := b.Build()
+						buf.WriteString(sql)
+						values = append(values, nestedArgs...)
+					} else {
+						buf.WriteRune('?')
+						values = append(values, arg)
+					}
 				}
 			}
 		}

delete.go

@@ -35,13 +35,13 @@ func (db *DeleteBuilder) DeleteFrom(table string) *DeleteBuilder {
 	return db
 }
 
-// Where sets expressions of WHERE in UPDATE.
+// Where sets expressions of WHERE in DELETE.
 func (db *DeleteBuilder) Where(andExpr ...string) *DeleteBuilder {
 	db.whereExprs = append(db.whereExprs, andExpr...)
 	return db
 }
 
-// String returns the compiled UPDATE string.
+// String returns the compiled DELETE string.
 func (db *DeleteBuilder) String() string {
 	s, _ := db.Build()
 	return s

insert.go

@@ -50,7 +50,7 @@ func (ib *InsertBuilder) Values(value ...interface{}) *InsertBuilder {
 	return ib
 }
 
-// String returns the compiled UPDATE string.
+// String returns the compiled DELETE string.
 func (ib *InsertBuilder) String() string {
 	s, _ := ib.Build()
 	return s

select.go

@@ -107,7 +107,7 @@ func (sb *SelectBuilder) Offset(offset int) *SelectBuilder {
 	return sb
 }
 
-// As returns an AS expreesion.
+// As returns an AS expression.
 func (sb *SelectBuilder) As(col, alias string) string {
 	return fmt.Sprintf("%v AS %v", Escape(col), Escape(alias))
 }

select_test.go

@@ -18,6 +18,10 @@ func ExampleSelectBuilder() {
 			sb.IsNull("id_card"),
 			sb.In("status", 1, 2, 5),
 		),
+		sb.NotIn(
+			"id",
+			NewSelectBuilder().Select("id").From("banned"),
+		), // Nested SELECT.
 		"modified_at > created_at + "+sb.Var(86400), // It's allowed to write arbitrary SQL.
 	)
 	sb.GroupBy("status").Having(sb.NotIn("status", 4, 5))
@@ -29,6 +33,6 @@ func ExampleSelectBuilder() {
 	fmt.Println(args)
 
 	// Output:
-	// SELECT DISTINCT id, name, COUNT(*) AS t FROM demo.user WHERE id > ? AND name LIKE ? AND (id_card IS NULL OR status IN (?, ?, ?)) AND modified_at > created_at + ? GROUP BY status HAVING status NOT IN (?, ?) ORDER BY modified_at ASC LIMIT 10 OFFSET 5
+	// SELECT DISTINCT id, name, COUNT(*) AS t FROM demo.user WHERE id > ? AND name LIKE ? AND (id_card IS NULL OR status IN (?, ?, ?)) AND id NOT IN (SELECT id FROM banned) AND modified_at > created_at + ? GROUP BY status HAVING status NOT IN (?, ?) ORDER BY modified_at ASC LIMIT 10 OFFSET 5
 	// [1234 %Du 1 2 5 86400 4 5]
 }