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This article is to share with you about the basic operation of MySQL query. The editor thought it was very practical, so I shared it with you as a reference. Let's follow the editor and have a look.

one。 The basic operation of query statement 1. Basic operation of query statement-select-from-where: constraints-group by: grouping-having: filtering-distinct: deduplicating-order by: sorting-limit: limiting the number of query records-aggregate function: count (count) max (maximum) Min (minimum) avg (average) sum (summation) II. Single table query 1, previous table and data preparation # create a department table create table emp (id int not null unique auto_increment, name varchar (20) not null, sex enum ('male','female') not null default' male', # mostly male age int (3) unsigned not null default 28, hire_date date not null, post varchar (50), post_comment varchar (100), salary double (15jue 2), office int # one room per department (depart_id int) # insert record # three departments: teaching, sales Operate insert into emp (name,sex,age,hire_date,post,salary,office,depart_id) values ('tank','male',17,'20170301',' Zhang Jiang first Shuai Image endorsement Department', 7300.33 Magi 401), # below is the Teaching Department ('egon','male',78,'20150302','teacher',1000000.31,401,1), (' kevin','male',81,'20130305','teacher',8300,401,1), ('jason','male',73,'20140701') 'teacher',3500,401,1), (' owen','male',28,'20121101','teacher',2100,401,1), ('jerry','female',18,'20110211','teacher',9000,401,1), (' big cake', 'male',18,'19000301','teacher',30000,401,1), (' sean','male',48,'20101111','teacher',10000,401,1), ('crooked', 'female',48,'20150311','sale',3000.13,402,2) # the following is the sales department ('Yaya', 'female',38,'20101101','sale',2000.35,402,2), (' Tintin', 'female',18,'20110312','sale',1000.37,402,2), (' Xing', 'female',18,'20160513','sale',3000.29,402,2), (' GE', 'female',28,'20170127','sale',4000.33,402,2), (' Zhangye', 'male',28,'20160311','operation'' 10000.13 male',18,'19970312','operation',20000,403,3 403), the following are the operating departments ('Cheng Yaojin', 'male',18,'19970312','operation',20000,403,3), (' Cheng Jiaoyin', 'female',18,'20130311','operation',19000,403,3), (' Cheng Jie Tong', 'male',18,'20150411','operation',18000,403,3), (' Cheng Jie tie', 'female',18,'20140512','operation',17000,403,3) # PS: if Chinese characters are inserted in the windows system, the result of select is blank. You can set all character codes to gbk- select * from emp; #. If there is too much data and it is messy, you can put +\ G-select * from emp\ G-select * from emp at the back of the table. # if there is too much data and messy, you can add\ G-select * from emp\ G at the back of the table. Emphasis: writing SQL statements must follow two points:-Writing order: # get two records with id 4 and 5 select * from emp where id > 3 and id

3 and id

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