sql alter column not null

a non-empty column to a column that can be empty and show the resultsMysql> ALTER TABLE Using_engineer modify time_abandon_stm char (+) null; Query OK, 0 rows affected (0.67 sec) records:0 duplicates:0 warnings:0mysql>describeusing_engineer; +------------------+----------+------+-----+---------+-------+ |field |Type|

: Renaming a tableexec sp_rename ' [Original table name] ', ' [New table name] '11: Rename the column nameexec sp_rename ' [table name]. [Column name] ', ' [table name]. [New column Name] 'Create Comments (n ' user ', n ' dbo ', n ' TABLE ' for fixed notation)12: Add descriptive information to the tableEXECUTE sp_addextendedproperty n ' ms_description ', ' Person

(100);ALTER TABLE name change column names varchar (100); MySQL alter usage 1: Delete Column ALTER table "table name" DROP "column name" 2: Adding columns ALTER table "table name"

Label: SQL Example 4–alter SQL Create /etc/my.cnf character show create database test; alter Database Test character set UTF8; alter database Test character set GBK; show create Table user1;

SQL ALTER TABLE syntax and example tutorial After the alter table statement allows you to change the structure of a TABLE, it is created. Address terms that can be added to a new column. Existing columns may be deleted from the Drop clause table. The syntax of the alter ta

SQL ALTER TABLE Syntax and instance tutorial The ALTER TABLE statement allows you to change the structure of a table after it has been created. New column can be added to the address clause. Existing columns may be deleted from the list of drop clauses used. The syntax for the AL