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MySQL查询语法汇总_Mysql_

2023-05-27 407人已围观

简介 MySQL查询语法汇总_Mysql_

前言：

本篇文章主要简介下MySQL中where,group by ,order by ,limit,join,union ,union all,子表等查询语法。

测试数据准备

 create table emp ( empno numeric(4) not null, ename varchar(10), job varchar(9), mgr numeric(4), hiredate datetime, sal numeric(7, 2), comm numeric(7, 2), deptno numeric(2)); create table dept ( deptno numeric(2), dname varchar(14), loc varchar(13)); create table salgrade ( grade numeric, losal numeric, hisal numeric); insert into dept values (10, 'ACCOUNTING', 'NEW YORK');insert into dept values (20, 'RESEARCH', 'DALLAS');insert into dept values (30, 'SALES', 'CHICAGO');insert into dept values (40, 'OPERATIONS', 'BOSTON'); insert into salgrade values (1, 700, 1200);insert into salgrade values (2, 1201, 1400);insert into salgrade values (3, 1401, 2000);insert into salgrade values (4, 2001, 3000);insert into salgrade values (5, 3001, 9999); insert into emp values (7369, 'SMITH', 'CLERK', 7902, '1980-12-17', 800, null, 20);insert into emp values (7499, 'ALLEN', 'SALESMAN', 7698, '1981-02-20', 1600, 300, 30);insert into emp values (7521, 'WARD', 'SALESMAN', 7698, '1981-02-22', 1250, 500, 30);insert into emp values (7566, 'JONES', 'MANAGER', 7839, '1981-04-02', 2975, null, 20);insert into emp values (7654, 'MARTIN', 'SALESMAN', 7698, '1981-09-28', 1250, 1400, 30);insert into emp values (7698, 'BLAKE', 'MANAGER', 7839, '1981-05-01', 2850, null, 30);insert into emp values (7782, 'CLARK', 'MANAGER', 7839, '1981-06-09', 2450, null, 10);insert into emp values (7788, 'SCOTT', 'ANALYST', 7566, '1982-12-09', 3000, null, 20);insert into emp values (7839, 'KING', 'PRESIDENT', null, '1981-11-17', 5000, null, 10);insert into emp values (7844, 'TURNER', 'SALESMAN', 7698, '1981-09-08', 1500, 0, 30);insert into emp values (7876, 'ADAMS', 'CLERK', 7788, '1983-01-12', 1100, null, 20);insert into emp values (7900, 'JAMES', 'CLERK', 7698, '1981-12-03', 950, null, 30);insert into emp values (7902, 'FORD', 'ANALYST', 7566, '1981-12-03', 3000, null, 20);insert into emp values (7934, 'MILLER', 'CLERK', 7782, '1982-01-23', 1300, null, 10);

1.模糊查询

 mysql> select * from emp where ename like '%S%'; +-------+-------+---------+------+---------------------+---------+------+--------+| empno | ename | job | mgr | hiredate | sal | comm | deptno |+-------+-------+---------+------+---------------------+---------+------+--------+| 7369 | SMITH | CLERK | 7902 | 1980-12-17 00:00:00 | 800.00 | NULL | 20 || 7566 | JONES | MANAGER | 7839 | 1981-04-02 00:00:00 | 2975.00 | NULL | 20 || 7788 | SCOTT | ANALYST | 7566 | 1982-12-09 00:00:00 | 3000.00 | NULL | 20 || 7876 | ADAMS | CLERK | 7788 | 1983-01-12 00:00:00 | 1100.00 | NULL | 20 || 7900 | JAMES | CLERK | 7698 | 1981-12-03 00:00:00 | 950.00 | NULL | 30 |+-------+-------+---------+------+---------------------+---------+------+--------+5 rows in set (0.00 sec) mysql> select * from emp where ename like 'S%'; +-------+-------+---------+------+---------------------+---------+------+--------+| empno | ename | job | mgr | hiredate | sal | comm | deptno |+-------+-------+---------+------+---------------------+---------+------+--------+| 7369 | SMITH | CLERK | 7902 | 1980-12-17 00:00:00 | 800.00 | NULL | 20 || 7788 | SCOTT | ANALYST | 7566 | 1982-12-09 00:00:00 | 3000.00 | NULL | 20 |+-------+-------+---------+------+---------------------+---------+------+--------+2 rows in set (0.01 sec) mysql> select * from emp where ename like '%S';+-------+-------+---------+------+---------------------+---------+------+--------+| empno | ename | job | mgr | hiredate | sal | comm | deptno |+-------+-------+---------+------+---------------------+---------+------+--------+| 7566 | JONES | MANAGER | 7839 | 1981-04-02 00:00:00 | 2975.00 | NULL | 20 || 7876 | ADAMS | CLERK | 7788 | 1983-01-12 00:00:00 | 1100.00 | NULL | 20 || 7900 | JAMES | CLERK | 7698 | 1981-12-03 00:00:00 | 950.00 | NULL | 30 |+-------+-------+---------+------+---------------------+---------+------+--------+3 rows in set (0.00 sec) mysql> select * from emp where ename like '_O%';+-------+-------+---------+------+---------------------+---------+------+--------+| empno | ename | job | mgr | hiredate | sal | comm | deptno |+-------+-------+---------+------+---------------------+---------+------+--------+| 7566 | JONES | MANAGER | 7839 | 1981-04-02 00:00:00 | 2975.00 | NULL | 20 || 7902 | FORD | ANALYST | 7566 | 1981-12-03 00:00:00 | 3000.00 | NULL | 20 |+-------+-------+---------+------+---------------------+---------+------+--------+2 rows in set (0.00 sec)

总结：%表示任意0个或多个字符，可匹配任意类型和长度的字符；_表示任意单个字符，匹配单个任意字符。

2.排序

 mysql> select * from emp order by sal;+-------+--------+-----------+------+---------------------+---------+---------+--------+| empno | ename | job | mgr | hiredate | sal | comm | deptno |+-------+--------+-----------+------+---------------------+---------+---------+--------+| 7369 | SMITH | CLERK | 7902 | 1980-12-17 00:00:00 | 800.00 | NULL | 20 || 7900 | JAMES | CLERK | 7698 | 1981-12-03 00:00:00 | 950.00 | NULL | 30 || 7876 | ADAMS | CLERK | 7788 | 1983-01-12 00:00:00 | 1100.00 | NULL | 20 || 7521 | WARD | SALESMAN | 7698 | 1981-02-22 00:00:00 | 1250.00 | 500.00 | 30 || 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 00:00:00 | 1250.00 | 1400.00 | 30 || 7934 | MILLER | CLERK | 7782 | 1982-01-23 00:00:00 | 1300.00 | NULL | 10 || 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 00:00:00 | 1500.00 | 0.00 | 30 || 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 00:00:00 | 1600.00 | 300.00 | 30 || 7782 | CLARK | MANAGER | 7839 | 1981-06-09 00:00:00 | 2450.00 | NULL | 10 || 7698 | BLAKE | MANAGER | 7839 | 1981-05-01 00:00:00 | 2850.00 | NULL | 30 || 7566 | JONES | MANAGER | 7839 | 1981-04-02 00:00:00 | 2975.00 | NULL | 20 || 7788 | SCOTT | ANALYST | 7566 | 1982-12-09 00:00:00 | 3000.00 | NULL | 20 || 7902 | FORD | ANALYST | 7566 | 1981-12-03 00:00:00 | 3000.00 | NULL | 20 || 7839 | KING | PRESIDENT | NULL | 1981-11-17 00:00:00 | 5000.00 | NULL | 10 |+-------+--------+-----------+------+---------------------+---------+---------+--------+14 rows in set (0.00 sec) mysql> select * from emp order by sal asc;+-------+--------+-----------+------+---------------------+---------+---------+--------+| empno | ename | job | mgr | hiredate | sal | comm | deptno |+-------+--------+-----------+------+---------------------+---------+---------+--------+| 7369 | SMITH | CLERK | 7902 | 1980-12-17 00:00:00 | 800.00 | NULL | 20 || 7900 | JAMES | CLERK | 7698 | 1981-12-03 00:00:00 | 950.00 | NULL | 30 || 7876 | ADAMS | CLERK | 7788 | 1983-01-12 00:00:00 | 1100.00 | NULL | 20 || 7521 | WARD | SALESMAN | 7698 | 1981-02-22 00:00:00 | 1250.00 | 500.00 | 30 || 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 00:00:00 | 1250.00 | 1400.00 | 30 || 7934 | MILLER | CLERK | 7782 | 1982-01-23 00:00:00 | 1300.00 | NULL | 10 || 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 00:00:00 | 1500.00 | 0.00 | 30 || 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 00:00:00 | 1600.00 | 300.00 | 30 || 7782 | CLARK | MANAGER | 7839 | 1981-06-09 00:00:00 | 2450.00 | NULL | 10 || 7698 | BLAKE | MANAGER | 7839 | 1981-05-01 00:00:00 | 2850.00 | NULL | 30 || 7566 | JONES | MANAGER | 7839 | 1981-04-02 00:00:00 | 2975.00 | NULL | 20 || 7788 | SCOTT | ANALYST | 7566 | 1982-12-09 00:00:00 | 3000.00 | NULL | 20 || 7902 | FORD | ANALYST | 7566 | 1981-12-03 00:00:00 | 3000.00 | NULL | 20 || 7839 | KING | PRESIDENT | NULL | 1981-11-17 00:00:00 | 5000.00 | NULL | 10 |+-------+--------+-----------+------+---------------------+---------+---------+--------+14 rows in set (0.00 sec) mysql> select * from emp order by sal desc;+-------+--------+-----------+------+---------------------+---------+---------+--------+| empno | ename | job | mgr | hiredate | sal | comm | deptno |+-------+--------+-----------+------+---------------------+---------+---------+--------+| 7839 | KING | PRESIDENT | NULL | 1981-11-17 00:00:00 | 5000.00 | NULL | 10 || 7788 | SCOTT | ANALYST | 7566 | 1982-12-09 00:00:00 | 3000.00 | NULL | 20 || 7902 | FORD | ANALYST | 7566 | 1981-12-03 00:00:00 | 3000.00 | NULL | 20 || 7566 | JONES | MANAGER | 7839 | 1981-04-02 00:00:00 | 2975.00 | NULL | 20 || 7698 | BLAKE | MANAGER | 7839 | 1981-05-01 00:00:00 | 2850.00 | NULL | 30 || 7782 | CLARK | MANAGER | 7839 | 1981-06-09 00:00:00 | 2450.00 | NULL | 10 || 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 00:00:00 | 1600.00 | 300.00 | 30 || 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 00:00:00 | 1500.00 | 0.00 | 30 || 7934 | MILLER | CLERK | 7782 | 1982-01-23 00:00:00 | 1300.00 | NULL | 10 || 7521 | WARD | SALESMAN | 7698 | 1981-02-22 00:00:00 | 1250.00 | 500.00 | 30 || 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 00:00:00 | 1250.00 | 1400.00 | 30 || 7876 | ADAMS | CLERK | 7788 | 1983-01-12 00:00:00 | 1100.00 | NULL | 20 || 7900 | JAMES | CLERK | 7698 | 1981-12-03 00:00:00 | 950.00 | NULL | 30 || 7369 | SMITH | CLERK | 7902 | 1980-12-17 00:00:00 | 800.00 | NULL | 20 |+-------+--------+-----------+------+---------------------+---------+---------+--------+14 rows in set (0.00 sec)

总结：order by排序默认按asc升序来排列也可指定desc降序排列

3.限制多少行

 mysql> select * from emp limit 3;+-------+-------+----------+------+---------------------+---------+--------+--------+| empno | ename | job | mgr | hiredate | sal | comm | deptno |+-------+-------+----------+------+---------------------+---------+--------+--------+| 7369 | SMITH | CLERK | 7902 | 1980-12-17 00:00:00 | 800.00 | NULL | 20 || 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 00:00:00 | 1600.00 | 300.00 | 30 || 7521 | WARD | SALESMAN | 7698 | 1981-02-22 00:00:00 | 1250.00 | 500.00 | 30 |+-------+-------+----------+------+---------------------+---------+--------+--------+3 rows in set (0.00 sec) mysql> select * from emp order by sal desc limit 3;+-------+
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