MySQL Basic Operation-sql Query statement

1. Querying data

Select Property List

From table name and view list

[Where Condition expression 1]

[Group By property name 1 [having conditional expression 2] [with rollup the last record is the sum of the above Records]]//The field specified by the attribute name 1 is grouped, there is having to satisfy the conditional expression 2

[Order BY property name 2 [Asc|desc]]

where query condition:

Compare =, <, <=, >, >=,! =, <>,!>,!<

Specify the range between and, not between and

Specifies the collection in, not in

Match characters like, don't like <%: represents any length string, _: Represents a single character >

Null value is NULL, is not NULL

Eg:select * from test0 where ID in (1001,1004,1005);

SELECT * from test0 where ID between 1002 and 1005;

SELECT * FROM test0 where ID < 1004 and name like ' H_h_ '; Two conditions are met

SELECT * FROM test0 where ID < 1004 or name like ' h% '; Meet one of them to

Select distinct name from Test0; Query results are not duplicated

Select Id,group_concat (name) from the Test0 group by name;//displays the specified field values in the name group

Select Name,count (name) from the TEST0 group by name;//counts the number of records in each group of name groupings

Select Name,count (name) from TEST0 group by name has count (name) > 1; Shows the number of records greater than 1

A having expression is a record that acts on a group, and where acts on a table or view.

Select Name,count (name) from TEST0 group by name with rollup;

SELECT * from Test0 limit 3; Show only 3 records

SELECT * from Test0 limit 1, 3; Showing 3 records from 2nd record

MySQL Basic Operation-sql Query statement