SQLite – HAVING子句
HAVING使您能够指定过滤条件哪一组结果出现在最终的结果。
WHERE子句的地方条件选定的列, 在有HAVING 子句的地方 就有GROUP BY子句包含的条件组.
语法：
下面是在一个SELECT子句的位置查询:
SELECT
FROM
WHERE
GROUP BY
HAVING
ORDER BY
HAVING 子句必须遵循的GROUP BY子句的查询,还必须先于ORDER BY如果使用它。
下面是SELECT语句的语法,包括有条款:
SELECT column1, column2
FROM table1, table2
WHERE [ conditions ]
GROUP BY column1, column2
HAVING [ conditions ]
ORDER BY column1, column2
例子：
COMPANY table有以下记录:
ID NAME AGE ADDRESS SALARY
---------- ---------- ---------- ---------- ----------
1 Paul 32 California 20000.0
2 Allen 25 Texas 15000.0
3 Teddy 23 Norway 20000.0
4 Mark 25 Rich-Mond 65000.0
5 David 27 Texas 85000.0
6 Kim 22 South-Hall 45000.0
7 James 24 Houston 10000.0
8 Paul 24 Houston 20000.0
9 James 44 Norway 5000.0
10 James 45 Texas 5000.0
以下是示例,显示记录的名字数小于2:
sqlite > SELECT * FROM COMPANY GROUP BY name HAVING count(name) < 2;
这将产生以下结果:
ID NAME AGE ADDRESS SALARY
---------- ---------- ---------- ---------- ----------
2 Allen 25 Texas 15000
5 David 27 Texas 85000
6 Kim 22 South-Hall 45000
4 Mark 25 Rich-Mond 65000
3 Teddy 23 Norway 20000
以下是示例,显示记录数大于2的名字:
sqlite > SELECT * FROM COMPANY GROUP BY name HAVING count(name) > 2;
这将产生以下结果:
ID NAME AGE ADDRESS SALARY
---------- ---------- ---------- ---------- ----------
10 James 45 Texas 5000