feat(delete): add using for postgres database

Author: webdaad

delete.go

@@ -13,6 +13,7 @@ const (
 	deleteMarkerInit injectionMarker = iota
 	deleteMarkerAfterWith
 	deleteMarkerAfterDeleteFrom
+	deleteMarkerAfterUsing
 	deleteMarkerAfterWhere
 	deleteMarkerAfterOrderBy
 	deleteMarkerAfterLimit
@@ -69,6 +70,7 @@ type DeleteBuilder struct {
 	cteBuilder    *CTEBuilder
 
 	tables      []string
+	usingTables []string
 	orderByCols []string
 	order       string
 	limitVar    string
@@ -102,6 +104,18 @@ func (db *DeleteBuilder) DeleteFrom(table ...string) *DeleteBuilder {
 	return db
 }
 
+// Using sets the USING clause in DELETE.
+// It's a PostgreSQL extension that allows referencing other tables in the WHERE clause,
+// similar to a JOIN.
+//
+//	db.DeleteFrom("orders").Using("customers").Where("orders.customer_id = customers.id", "customers.status = 'inactive'")
+//	// Generates: DELETE FROM orders USING customers WHERE orders.customer_id = customers.id AND customers.status = 'inactive'
+func (db *DeleteBuilder) Using(table ...string) *DeleteBuilder {
+	db.usingTables = table
+	db.marker = deleteMarkerAfterUsing
+	return db
+}
+
 // TableNames returns all table names in this DELETE statement.
 func (db *DeleteBuilder) TableNames() []string {
 	var additionalTableNames []string
@@ -264,6 +278,13 @@ func (db *DeleteBuilder) BuildWithFlavor(flavor Flavor, initialArg ...interface{
 		db.injection.WriteTo(buf, insertMarkerAfterReturning)
 	}
 
+	if len(db.usingTables) > 0 {
+		buf.WriteLeadingString("USING ")
+		buf.WriteStrings(db.usingTables, ", ")
+	}
+
+	db.injection.WriteTo(buf, deleteMarkerAfterUsing)
+
 	if db.WhereClause != nil {
 		db.whereClauseProxy.WhereClause = db.WhereClause
 		defer func() {

delete_test.go

@@ -194,6 +194,67 @@ func TestDeleteBuilderReturning(t *testing.T) {
 	a.Equal("WITH temp_user AS (SELECT id FROM inactive_users) DELETE FROM user, temp_user WHERE user.id IN (SELECT id FROM temp_user) RETURNING id, deleted_at", sql)
 }
 
+func ExampleDeleteBuilder_Using() {
+	db := NewDeleteBuilder()
+	db.DeleteFrom("orders")
+	db.Using("customers")
+	db.Where(
+		"orders.customer_id = customers.id",
+		db.Equal("customers.status", "inactive"),
+	)
+
+	sql, args := db.BuildWithFlavor(PostgreSQL)
+	fmt.Println(sql)
+	fmt.Println(args)
+
+	// Output:
+	// DELETE FROM orders USING customers WHERE orders.customer_id = customers.id AND customers.status = $1
+	// [inactive]
+}
+
+func TestDeleteBuilderUsing(t *testing.T) {
+	a := assert.New(t)
+
+	// Single USING table
+	db := NewDeleteBuilder()
+	db.DeleteFrom("orders")
+	db.Using("customers")
+	db.Where("orders.customer_id = customers.id")
+
+	sql, _ := db.BuildWithFlavor(PostgreSQL)
+	a.Equal("DELETE FROM orders USING customers WHERE orders.customer_id = customers.id", sql)
+
+	// Multiple USING tables
+	db2 := NewDeleteBuilder()
+	db2.DeleteFrom("orders")
+	db2.Using("customers", "products")
+	db2.Where("orders.customer_id = customers.id", "orders.product_id = products.id")
+
+	sql, _ = db2.BuildWithFlavor(PostgreSQL)
+	a.Equal("DELETE FROM orders USING customers, products WHERE orders.customer_id = customers.id AND orders.product_id = products.id", sql)
+
+	// USING with RETURNING
+	db3 := NewDeleteBuilder()
+	db3.DeleteFrom("orders")
+	db3.Using("customers")
+	db3.Where(db3.Equal("customers.id", 42))
+	db3.Returning("orders.id")
+
+	sql, args := db3.BuildWithFlavor(PostgreSQL)
+	a.Equal("DELETE FROM orders USING customers WHERE customers.id = $1 RETURNING orders.id", sql)
+	a.Equal([]interface{}{42}, args)
+
+	// SQL injection after USING
+	db4 := NewDeleteBuilder()
+	db4.DeleteFrom("orders")
+	db4.Using("customers")
+	db4.SQL("/* after using */")
+	db4.Where("orders.customer_id = customers.id")
+
+	sql, _ = db4.BuildWithFlavor(PostgreSQL)
+	a.Equal("DELETE FROM orders USING customers /* after using */ WHERE orders.customer_id = customers.id", sql)
+}
+
 func TestDeleteBuilderClone(t *testing.T) {
 	a := assert.New(t)
 	cte := With(

go.mod

@@ -1,4 +1,4 @@
-module github.com/huandu/go-sqlbuilder
+module github.com/webdaad/go-sqlbuilder
 
 go 1.18