SQLite Having 子句

SQLite Having 子句HAVING 子句允许指定条件来过滤将出现在最终结果中的分组结果。WHERE 子句在所选列上设置条件，而 HAVING 子句则在由 GROUP BY 子句创建的分组上设置条件。语法下面是 HAVING 子句在 SELECT 查询中的位置：SELECTFROMWHEREGROUP BYHAVINGORDER BY在一个查询中，HAVING 子句必须放在 GROUP BY 子句之后，必须放在 ORDER BY 子句之前。下面是包含 HAVING 子句的 SELECT 语句的语法：SELECT column1, column2FROM table1, table2WHERE [ conditions ]GROUP BY column1, column2HAVING [ conditions ]ORDER BY column1, column2实例假设 COMPANY 表有以下记录：ID NAME AGE ADDRESS SALARY---------- ---------- ---------- ---------- ----------1 Paul 32 California 20000.02 Allen 25 Texas 15000.03 Teddy 23 Norway 20000.04 Mark 25 Rich-Mond 65000.05 David 27 Texas 85000.06 Kim 22 South-Hall 45000.07 James 24 Houston 10000.08 Paul 24 Houston 20000.09 James 44 Norway 5000.010 James 45 Texas 5000.0下面是一个实例，它将显示名称计数小于 2 的所有记录：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 150005 David 27 Texas 850006 Kim 22 South-Hall 450004 Mark 25 Rich-Mond 650003 Teddy 23 Norway 20000下面是一个实例，它将显示名称计数大于 2 的所有记录：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