Implementation of MySQL asc and desc data sorting

Data sorting asc, desc

1. Single field sorting order by field name

Function: Which field or fields to sort by

Meaning: Sorting uses the order by clause, followed by the sorting field. You can put multiple sorting fields, separated by commas. Order by default uses ascending order (asc). If there is a where clause, then order by must be placed after the where clause.

(1) Sort by salary from small to large (the system defaults to small to large)

For example: select ename,sal from emp order by sal;

(2) Get employees whose job is MANAGER and sort them by salary from small to large (the system defaults to small to large)

For example: select ename,job,sal from emp where job = ”MANAGER”order by sal;

If a where clause is included, order by must be placed after where; if there is no where clause, order by is placed after the table;

(3) The following inquiry method is wrong:

select * from emp order by sal whereselect * from emp order by sal where job = 'MANAGER'; 

2. Manually specify field sorting

(1) Manually specify the sorting by salary from small to large (ascending keyword asc)

For example: select ename,sal from emp order by sal asc;

(2) Manually specify the sorting by salary from high to low (descending keyword desc)

For example: select ename,sal from emp order by sal desc;

3. Sorting multiple fields

(1) Sort by job and salary in descending order

For example: select ename,job,ename from emp order by job desc,sal desc;

Note: If multiple fields are used for sorting, if the sorting based on the first field is repeated, the sorting will be based on the second field;

4. Sort by field position

(1) Sort by salary in ascending order (this method is not recommended, as the meaning of the numbers is unclear, readability is poor, and the program is not robust)

select * from emp order by 6; 

The above is the full content of this article. I hope it will be helpful for everyone’s study. I also hope that everyone will support 123WORDPRESS.COM.