如何计算有多少人使用相同的id

Question

我有一张表是工作人员。该列为id_staff, no_staff和id_posting。我想算一下有多少人使用相同的id_posting。任何人都可以帮我查询吗？谢谢。

Answer 1

您是否尝试过自己进行查询？ 这是非常基本的

select count(id_staff), id_posting from staff where id_posting = ? group by id_posting

Answer 2

select COUNT(*) AS ID_COUNT from YOUR_TABLE group by THE_ID_WHICH_IS_REPEATED

http://www.w3schools.com/sql/sql_func_count.asp 查看教程以获取更多信息。

Answer 3

请试试这个

SELECT id_posting ,COUNT( `id_staff` ) as cnt_staff
FROM table_staff
GROUP BY id_posting