平时少用到的sql query

查找第三个字符是'i'的结果：

select col_1 from tab_1 where col_1 like '__i%';

查找在1到7之间的结果：

select col_1 from tab_1 where col_1 between 1 and 7;

在where中使用select语句：

select col_1 from tab_1 where col_2 = (select count(*) from tab_2);

组合表查询：

select tab_1.col_1, tab_2.col_1, col_2 from tab_1, tab_2 where tab_1.col_1 = tab_2.col_1;