Summary of the use of common commands for mysql columns

The main content of this article is mysql column common commands:

1. View table column attributesdescribe table_name column_name

2. show all column property View the properties of all columns

3. Modify the column properties of the table alter table

   modify

   rename columnRename column

   Add column (add index at the same time), delete column

   Modify the default value of the column

   ---

   View the attributes of the table columndescribe table_name column_name

   ---

   Many times we need to view the column Details, for example:

   describe springdemo.blog title;

   

   show all column propertyView the properties of all columns

   ---

   show fields from springdemo.blog;

   View all columns

   

   Modify the column attributes of the table alter table

   modify

   ---

   Modify the column attributes of the table alter table

   modify

   

   ##rename columnRename column

   ---

   Modify the field name of the table alter table

   change

   

   Note: The storage of data in the database has a great relationship with the data type, so do not change the data type casually

   alter table springdemo.blog change title title_new nvarchar(60) comment 'Modified';
   

   Add (add index at the same time), delete columns

   alter table springdemo.tb_ms_audit_user_infoadd mal_report int default 0comment '恶意举报的次数', add index(mal_report);

   删除字段 : alter  table  <表名>  drop  <列名>

   ---

   Modify the default value of the column

   alter table tablename alter column drop default; #(若本身存在默认值，则先删除)alter table tablename alter column set default 't5';# (若本身不存在则可以直接设定)

   Be sure to indicate the source when reprinting, and respect the work of others.

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