Java教程

SQL53 按照dept_no进行汇总

本文主要是介绍SQL53 按照dept_no进行汇总,对大家解决编程问题具有一定的参考价值,需要的程序猿们随着小编来一起学习吧!

描述

按照dept_no进行汇总,属于同一个部门的emp_no按照逗号进行连接,结果给出dept_no以及连接出的结果employees
CREATE TABLE `dept_emp` (
`emp_no` int(11) NOT NULL,
`dept_no` char(4) NOT NULL,
`from_date` date NOT NULL,
`to_date` date NOT NULL,
PRIMARY KEY (`emp_no`,`dept_no`));
输出格式:

dept_noemployees
d00110001,10002
d00210006
d00310005
d00410003,10004
d00510007,10008,10010
d00610009,10010

示例1

输入:

drop table if exists  `dept_emp` ; 
CREATE TABLE `dept_emp` (
`emp_no` int(11) NOT NULL,
`dept_no` char(4) NOT NULL,
`from_date` date NOT NULL,
`to_date` date NOT NULL,
PRIMARY KEY (`emp_no`,`dept_no`));
INSERT INTO dept_emp VALUES(10001,'d001','1986-06-26','9999-01-01');
INSERT INTO dept_emp VALUES(10002,'d001','1996-08-03','9999-01-01');
INSERT INTO dept_emp VALUES(10003,'d004','1995-12-03','9999-01-01');
INSERT INTO dept_emp VALUES(10004,'d004','1986-12-01','9999-01-01');
INSERT INTO dept_emp VALUES(10005,'d003','1989-09-12','9999-01-01');
INSERT INTO dept_emp VALUES(10006,'d002','1990-08-05','9999-01-01');
INSERT INTO dept_emp VALUES(10007,'d005','1989-02-10','9999-01-01');
INSERT INTO dept_emp VALUES(10008,'d005','1998-03-11','2000-07-31');
INSERT INTO dept_emp VALUES(10009,'d006','1985-02-18','9999-01-01');
INSERT INTO dept_emp VALUES(10010,'d005','1996-11-24','2000-06-26');
INSERT INTO dept_emp VALUES(10010,'d006','2000-06-26','9999-01-01');

复制输出:

d001|10001,10002
d002|10006
d003|10005
d004|10003,10004
d005|10007,10008,10010
d006|10009,10010
/*题目:SQL53 按照dept_no进行汇总.
-- 聚合函数group_concat(X,Y),其中X是要连接的字段,Y是连接时用的符号,可省略,默认为逗号
*/
select 
    d.dept_no,
    group_concat(emp_no)
from
    dept_emp d
GROUP BY
    d.dept_no

这篇关于SQL53 按照dept_no进行汇总的文章就介绍到这儿,希望我们推荐的文章对大家有所帮助,也希望大家多多支持为之网!