MySQL's advanced additions and deletions to a

One, select all/distinct field name/alias from table where Condition + "1" + "2" + "3";

Where Condition: >,<,≥,≤,like,between and (closed interval), in, No in, with &&, or | |, non!

All: Query go all

Distinct: Remove Duplicate results

"1": Group BY "ASC/DESC" ASC: Ascending, desc: Descending

"2": ORDER BY

"3": Limit limit 3: Take the first 3 records; limit 2, 3: Starting from the third record, Fetch 3 records (starting from position 2, length 3)

1, example demonstration

First build a table, ID primary key (primary key), and self-growth (auto_increment)

CREATE TABLE TESTABC (ID int primary KEY auto_increment,name varchar (4));

Add data

INSERT into TESTABC set name= ' a ';

Bulk Add

Insert into TESTABC (name) VALUES (' a '), (' B '), (' C '), (' C '), (' A '), (' a ');

SELECT * from TESTABC where name= ' a ';

SELECT * FROM TESTABC group by name;

Limit the top 3 select * from TESTABC limit 3;

SELECT * from TESTABC limit 2, 3; Starting from the third record, Fetch 3 records (starting from position 2, length is 3)

Second, common function Max (), Min (), AVG (), COUNT (), COUNT ()---record value is null when no count in

1, examples of demonstration, the table is as follows

Select Max (age) from Stu;

Select Sex, COUNT (*) from Stu Group by sex;

Select Sex,count (*), Max (age), AVG (age) from Stu Group by sex;

MySQL's advanced additions and deletions to a