我尝试了以下,但我有一个语法错误
ALTER TABLE Grades ( DROP COLUMN (Student_FamilyName,Student_Name),ADD Student_id INT );
是否可以在相同的ALTER TABLE语句中执行DROP和ADD？
解决方法
如果你看看
ALTER TABLE SYTAX
你会看到这个
ALTER TABLE [ database_name . [ schema_name ] . | schema_name . ] table_name
{
ALTER COLUMN column_name
{
[ type_schema_name. ] type_name [ ( { precision [,scale ]
| max | xml_schema_collection } ) ]
[ COLLATE collation_name ]
[ NULL | NOT NULL ] [ SPARSE ]
| {ADD | DROP }
{ ROWGUIDCOL | PERSISTED | NOT FOR REPLICATION | SPARSE }
}
| [ WITH { CHECK | NOCHECK } ]
| ADD
{
<column_definition>
| <computed_column_definition>
| <table_constraint>
| <column_set_definition>
} [,...n ]
| DROP
{
[ CONSTRAINT ]
{
constraint_name
[ WITH
( <drop_clustered_constraint_option> [,...n ] )
]
} [,...n ]
| COLUMN
{
column_name
} [,...n ]
} [,...n ]
这可以减少到
ALTER TABLE {ALTER COLUMN column_name |添加| DROP}
根据Transact-SQL Syntax Conventions (Transact-SQL) (垂直条)
Separates Syntax items enclosed in brackets or braces. You can use only one of the items.
所以你不能在一个语句中改变,删除或添加.你也有括号和逗号不起作用.所以你需要
ALTER TABLE Grades DROP COLUMN (Student_FamilyName,Student_Name); ALTER TABLE Grades ADD Student_id INT;
如果你需要它们是一个原子行为,你只需要包装交易
