MySQL问题，谢谢
1) . select * from demo where id<=10 and name='zhangsan' and (sex='0' or 'age'>=18);
2).select * from demo where id<=10 and name='zhangsan' and sex='0' or 'age'>=18;
3).select * from demo where id<=10 and name='zhangsan' and sex='0' and 'age'>=18;
4). select * from demo where id<=10 and name='zhangsan' and (sex='0' and 'age'>=18);
我弄不清楚 1和2的区别 3和4的区别，谢谢大神，能指点下吗？
数据库 mysql postgresq oracle sql
cgbugs
10 years, 4 months ago
