Collection of SQL statements from alter table in MySql database

mysql alter table collection of SQL statements, including add, modify, delete fields, rename tables, add, delete primary keys, etc.

1: Delete columns

ALTER TABLE [Table name] DROP [column name]

2: Add columns

ALTER TABLE [table name] ADD [column name] INT NOT NULL COMMENT 'Notes'

3: Modify the type information for the column

ALTER TABLE [Table name] CHANGE [Column name] BIGINT NOT NULL COMMENT [New column name] BIGINT NOT NULL COMMENT

4: Rename columns

ALTER TABLE [Table name] CHANGE [column name] [New column name] BIGINT NOT NULL COMMENT

5: Rename the table

ALTER TABLE [Table name]

6: Delete the primary key in the table

Alter TABLE [table name] drop primary key

7: Add the primary key

ALTER TABLE sj_resource_charges ADD CONSTRAINT PK_SJ_RESOURCE_CHARGES PRIMARY KEY (resid,resfromid)

8: Add indexes

ALTER TABLE sj_resource_charges add index INDEX_NAME (name);

9: Add index with only 1 constraint

ALTER TABLE sj_resource_charges add unique emp_name2(cardnumber);

10: Drop the index

alter table tablename drop index emp_name;

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