卖灯杆的做网站好,网站建设策划书 范文,海南明确2023年封岛,wordpress搜索结果不存在页面排序数据普通字段排序按照单一字段排序按照多个字段排序手动指定排序顺序单个字段手动排序多个字段手动排序普通字段排序按照单一字段排序排序采用order by子句#xff0c;order by后面跟上排序字段#xff0c;排序字段可以放多个#xff0c;多个采用逗号间隔#xff0c;or…排序数据普通字段排序按照单一字段排序按照多个字段排序手动指定排序顺序单个字段手动排序多个字段手动排序普通字段排序按照单一字段排序排序采用order by子句order by后面跟上排序字段排序字段可以放多个多个采用逗号间隔order by默认采用升序如果存在where子句那么order by必须放到where语句的后面。select * from emp order by sal;| EMPNO | ENAME | JOB | MGR | HIREDATE | SAL | COMM | DEPTNO |----------------------------------------------------------------------| 7369 | SMITH | CLERK | 7902 | 1980-12-17 | 800.00 | NULL | 20 || 7900 | JAMES | CLERK | 7698 | 1981-12-03 | 950.00 | NULL | 30 || 7876 | ADAMS | CLERK | 7788 | 1987-05-23 | 1100.00 | NULL | 20 || 7521 | WARD | SALESMAN | 7698 | 1981-02-22 | 1250.00 | 500.00 | 30 || 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 | 1250.00 | 1400.00 | 30 || 7934 | MILLER | CLERK | 7782 | 1982-01-23 | 1300.00 | NULL | 10 || 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 | 1500.00 | 0.00 | 30 || 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 | 1600.00 | 300.00 | 30 || 7782 | CLARK | MANAGER | 7839 | 1981-06-09 | 2450.00 | NULL | 10 || 7698 | BLAKE | MANAGER | 7839 | 1981-05-01 | 2850.00 | NULL | 30 || 7566 | JONES | MANAGER | 7839 | 1981-04-02 | 2975.00 | NULL | 20 || 7788 | SCOTT | ANALYST | 7566 | 1987-04-19 | 3000.00 | NULL | 20 || 7902 | FORD | ANALYST | 7566 | 1981-12-03 | 3000.00 | NULL | 20 || 7839 | KING | PRESIDENT | NULL | 1981-11-17 | 5000.00 | NULL | 10 |----------------------------------------------------------------------select * from emp where jobMANAGER order by sal;| EMPNO | ENAME | JOB | MGR | HIREDATE | SAL | COMM | DEPTNO |----------------------------------------------------------------| 7782 | CLARK | MANAGER | 7839 | 1981-06-09 | 2450.00 | NULL | 10 || 7698 | BLAKE | MANAGER | 7839 | 1981-05-01 | 2850.00 | NULL | 30 || 7566 | JONES | MANAGER | 7839 | 1981-04-02 | 2975.00 | NULL | 20 |----------------------------------------------------------------按照多个字段排序按照多个字段排序按前后顺序先出现的先进行排序。如首先进行job排序再进行sal排序。select * from emp order by job,sal;| EMPNO | ENAME | JOB | MGR | HIREDATE | SAL | COMM | DEPTNO |----------------------------------------------------------------------| 7788 | SCOTT | ANALYST | 7566 | 1987-04-19 | 3000.00 | NULL | 20 || 7902 | FORD | ANALYST | 7566 | 1981-12-03 | 3000.00 | NULL | 20 || 7369 | SMITH | CLERK | 7902 | 1980-12-17 | 800.00 | NULL | 20 || 7900 | JAMES | CLERK | 7698 | 1981-12-03 | 950.00 | NULL | 30 || 7876 | ADAMS | CLERK | 7788 | 1987-05-23 | 1100.00 | NULL | 20 || 7934 | MILLER | CLERK | 7782 | 1982-01-23 | 1300.00 | NULL | 10 || 7782 | CLARK | MANAGER | 7839 | 1981-06-09 | 2450.00 | NULL | 10 || 7698 | BLAKE | MANAGER | 7839 | 1981-05-01 | 2850.00 | NULL | 30 || 7566 | JONES | MANAGER | 7839 | 1981-04-02 | 2975.00 | NULL | 20 || 7839 | KING | PRESIDENT | NULL | 1981-11-17 | 5000.00 | NULL | 10 || 7521 | WARD | SALESMAN | 7698 | 1981-02-22 | 1250.00 | 500.00 | 30 || 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 | 1250.00 | 1400.00 | 30 || 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 | 1500.00 | 0.00 | 30 || 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 | 1600.00 | 300.00 | 30 |----------------------------------------------------------------------手动指定排序顺序单个字段手动排序默认是升序。怎么指定升序或者降序呢asc表示升序desc表示降序。select * from emp order by sal desc;//降序| EMPNO | ENAME | JOB | MGR | HIREDATE | SAL | COMM | DEPTNO |----------------------------------------------------------------------| 7839 | KING | PRESIDENT | NULL | 1981-11-17 | 5000.00 | NULL | 10 || 7788 | SCOTT | ANALYST | 7566 | 1987-04-19 | 3000.00 | NULL | 20 || 7902 | FORD | ANALYST | 7566 | 1981-12-03 | 3000.00 | NULL | 20 || 7566 | JONES | MANAGER | 7839 | 1981-04-02 | 2975.00 | NULL | 20 || 7698 | BLAKE | MANAGER | 7839 | 1981-05-01 | 2850.00 | NULL | 30 || 7782 | CLARK | MANAGER | 7839 | 1981-06-09 | 2450.00 | NULL | 10 || 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 | 1600.00 | 300.00 | 30 || 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 | 1500.00 | 0.00 | 30 || 7934 | MILLER | CLERK | 7782 | 1982-01-23 | 1300.00 | NULL | 10 || 7521 | WARD | SALESMAN | 7698 | 1981-02-22 | 1250.00 | 500.00 | 30 || 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 | 1250.00 | 1400.00 | 30 || 7876 | ADAMS | CLERK | 7788 | 1987-05-23 | 1100.00 | NULL | 20 || 7900 | JAMES | CLERK | 7698 | 1981-12-03 | 950.00 | NULL | 30 || 7369 | SMITH | CLERK | 7902 | 1980-12-17 | 800.00 | NULL | 20 |----------------------------------------------------------------------select * from emp order by sal asc;//升序| EMPNO | ENAME | JOB | MGR | HIREDATE | SAL | COMM | DEPTNO |----------------------------------------------------------------------| 7369 | SMITH | CLERK | 7902 | 1980-12-17 | 800.00 | NULL | 20 || 7900 | JAMES | CLERK | 7698 | 1981-12-03 | 950.00 | NULL | 30 || 7876 | ADAMS | CLERK | 7788 | 1987-05-23 | 1100.00 | NULL | 20 || 7521 | WARD | SALESMAN | 7698 | 1981-02-22 | 1250.00 | 500.00 | 30 || 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 | 1250.00 | 1400.00 | 30 || 7934 | MILLER | CLERK | 7782 | 1982-01-23 | 1300.00 | NULL | 10 || 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 | 1500.00 | 0.00 | 30 || 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 | 1600.00 | 300.00 | 30 || 7782 | CLARK | MANAGER | 7839 | 1981-06-09 | 2450.00 | NULL | 10 || 7698 | BLAKE | MANAGER | 7839 | 1981-05-01 | 2850.00 | NULL | 30 || 7566 | JONES | MANAGER | 7839 | 1981-04-02 | 2975.00 | NULL | 20 || 7788 | SCOTT | ANALYST | 7566 | 1987-04-19 | 3000.00 | NULL | 20 || 7902 | FORD | ANALYST | 7566 | 1981-12-03 | 3000.00 | NULL | 20 || 7839 | KING | PRESIDENT | NULL | 1981-11-17 | 5000.00 | NULL | 10 |----------------------------------------------------------------------多个字段手动排序按照工资的降序排列当工资相同的时候再按照名字的升序排列。select * from emp order by job desc, sal desc;| EMPNO | ENAME | JOB | MGR | HIREDATE | SAL | COMM | DEPTNO |----------------------------------------------------------------------| 7839 | KING | PRESIDENT | NULL | 1981-11-17 | 5000.00 | NULL | 10 || 7902 | FORD | ANALYST | 7566 | 1981-12-03 | 3000.00 | NULL | 20 || 7788 | SCOTT | ANALYST | 7566 | 1987-04-19 | 3000.00 | NULL | 20 || 7566 | JONES | MANAGER | 7839 | 1981-04-02 | 2975.00 | NULL | 20 || 7698 | BLAKE | MANAGER | 7839 | 1981-05-01 | 2850.00 | NULL | 30 || 7782 | CLARK | MANAGER | 7839 | 1981-06-09 | 2450.00 | NULL | 10 || 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 | 1600.00 | 300.00 | 30 || 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 | 1500.00 | 0.00 | 30 || 7934 | MILLER | CLERK | 7782 | 1982-01-23 | 1300.00 | NULL | 10 || 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 | 1250.00 | 1400.00 | 30 || 7521 | WARD | SALESMAN | 7698 | 1981-02-22 | 1250.00 | 500.00 | 30 || 7876 | ADAMS | CLERK | 7788 | 1987-05-23 | 1100.00 | NULL | 20 || 7900 | JAMES | CLERK | 7698 | 1981-12-03 | 950.00 | NULL | 30 || 7369 | SMITH | CLERK | 7902 | 1980-12-17 | 800.00 | NULL | 20 |----------------------------------------------------------------------越靠前的字段越能起到主导作用。只有当前面的字段无法完成排序的时候才会启用后面的字段。
