MySQl basic syntax (1)

Database Management

• View all databases: show database;
• Create a database: create databse;
• Create a data view database statement: show create database database name;
• Delete the database: drop database database name;

Management table

• View all the tables: show table;

• Create a table:CREATE TABLE student(id INT,
  NAME CHAR(20),
  sex CHAR(5),
  address CHAR(20),
  math INT,
  chinese INT);

• Lookup table structure: show create table table name; (sql to return)
  desc table;

• Delete tables: drop table name;

Data Management:

• Insert data: INSERT INTO student (column name) VALUES (default value);
• change the data:set update table column name = value where conditions
• delete data:delect from table where conditions

Query data:

• select * from 表名 · distinct keywords used to remove duplicate data

Conditions inquiry

(1) display within a certain range: between. . . and. .
(2) a value consistent with multiple conditions: in
(3) fuzzy query: like% matches any number of characters _ matches one

Sort query

• Sort separate
  select field names from table where field = value of the order by the field name [ASC || DESC]
  ASC ASC
  DES Descending
• Sort combination
  se'lselect field names from table where field = field name value order by ASC || DESC [1], [2 Field Name] ASC || DESC

Aggregation function:

Some of the above operation, the query is transverse, but the polymerization is longitudinal query function
max () selecting the maximum value of a
min () seeking a minimum value
AVG () column averaging the
count () lists the statistics how many record
sum () and find this column

Grouping:

select field form table gruop by field conditions [having]
group by generally to an aggregation function and use;
group by the results of the field is divided into the same group;

And where the difference between having

Interview questions:

limit Keywords:

     limit 限制查询记录的条件

grammar:

           limit offset，length  
           offset 起始行数，默认从0开始
           length 返回的行数

For example: