小程序云开发那个数据库，请问如何实现下面这种子查询啊 [代码]delete[代码] [代码]from[代码] [代码]table_a [代码][代码]where[代码] [代码]url [代码][代码]in[代码] [代码]([代码][代码]select[代码] [代码]url [代码][代码]from[代码] [代码]table_b [代码][代码]where[代码] [代码]source = [代码][代码]'XXXX'[代码][代码]);[代码]