摘要：
idea 显示行号设置：File->Settings->Editor->General->Appearance->show line numbers 阅读全文
摘要：
select * from a where 1=1 (and a.id is null or a.id = 0) 执行出错 select * from a where 1=1 and (a.id is null or a.id = 0) 执行正常说明1：使用 or 关键字最好要用括号把条件括起来说明 阅读全文