ALTER TABLE db_name.table_name COMMENT 'comment' 示例 将customer表的Comment变更为顾客表。 ALTER TABLE customer COMMENT '顾客表';; 列 增加列 语法 ALTER TABLE db_name.table_name ADD [COLUMN] {column_name column_type [DEFAULT {constant|CURRENT_TIMESTAMP}|AUTO_INCREMENT] [NULL|NOT NULL] [COMM...
syntaxsql 複製 ALTER COLUMN ENCRYPTION KEY key_name [ ADD | DROP ] VALUE ( COLUMN_MASTER_KEY = column_master_key_name [, ALGORITHM = 'algorithm_name' , ENCRYPTED_VALUE = varbinary_literal ] ) [;] 引數key_name 要變更的資料行加密金鑰。column_master_key_name 指定要用來加密資料行加密金...
syntaxsql Copy ALTER TABLE { database_name.schema_name.table_name | schema_name.table_name | table_name } { ALTER COLUMN column_name { [ type_schema_name. ] type_name [ ( { precision [ , scale ] } ) ] [ COLLATE collation_name ] [ NULL | NOT NULL ] } | ALTER INDEX index_...
ALTERTABLEtable_name ADDcolumn_name datatype; The following SQL adds an "Email" column to the "Customers" table: ExampleGet your own SQL Server ALTERTABLECustomers ADDEmail varchar(255); ALTER TABLE - DROP COLUMN To delete a column in a table, use the following syntax (notice that some da...
Syntax ALTER TABLEtable-Name{ ADD COLUMNcolumn-definition| ADDCONSTRAINT clause| DROP [ COLUMN ] column-name [ CASCADE | RESTRICT ] DROP { PRIMARY KEY | FOREIGN KEY constraint-name | UNIQUE constraint-name | CHECK constraint-name | CONSTRAINT constraint-name } ...
The proposed syntax is : ALTER TABLE ... RENAME COLUMN old_name TO new_name; This worklog will do the parser changes and implement the syntax changes. The new proposed syntax is expected to behave the same as "ALTER TABLE ... CHANGE" command used to rename column, without changing ...
ALTER TABLE table_name { ADD COLUMN clause | ALTER COLUMN clause | DROP COLUMN clause | RENAME COLUMN clause } ADD COLUMN 子句JDBC 数据源不支持此子句。向表添加一列或多列,或将字段添加到 Delta Lake 表中的现有列。备注 向现有 Delta 表添加列时,无法定义 DEFAULT 值。 对于现有行,...
syntaxsql ALTERDATABASEdatabase_name{<add_or_modify_files>|<add_or_modify_filegroups>}<add_or_modify_files>::={ADDFILE<filespec>[ ,...n ] [TOFILEGROUP{filegroup_name} ] |ADDLOGFILE<filespec>[ ,...n ] |REMOVEFILElogical_file_name|MODIFYFILE<filespec>}<filespec>::=(NAME=logical_file...
使用双向赋值(如UPDATE T1 SET @v = column_name = <expression>)来更新列会产生意外后果,因为在语句执行过程中,可以在其他子句(如WHERE和ON子句)中使用变量的实时值,而不是使用语句起始值。 这会导致谓词的含义无法预测地逐行变化。 只有在兼容性级别设置为 90 时,此行为才适用。使用双向赋值来更新列会产生预...
Column or parameter names within an object Index names within a table Duplicate names resulting from the new collation cause the change action to fail, and SQL Server returns an error message specifying the namespace where the duplicate was found. ...