2.1. 暂不支持的SQL语句 1、不支持select *，如select *from a,b 2、不支持不带表别名的字段，所有表和字段必须有别名。 正确写法：select t.id,o.id from customer t ,order o where t.customer_id=o.customer_id; 错误写法：select id,o.id from customer t ,order o where t.customer_id=o.customer_id; 3、不支持case when语句 4、不支持条件两边都是常量，如 where 1=1 5、不支持having中条件中带in,!=,如 having t.customer_id IN(1,2,3) 6、不支持越层的嵌套子查询，如下面的语句select c.id from customer c where exists (select 1 from order o where o.order_id in(select oo.order_id from order oo where oo.customer_id = c.customer_id))，条件oo.customer_id = c.customer_id属于越层关联 7、不支持带or、括号的语句 8、不支持函数内部的字段跨库，如 select t.customer_id,CONCAT(s.customer_id,t.customer_id) from customer t ,customer_order s
