ALTER TABLE 语句的语法格式为: ALTERTABLEtable {[ALTER COLUMN column_name { new_data_type [ (precision[, scale]) ] [NULL | NOT NULL] |{ADD|DROP}ROWGUIDCOL } ] |ADD {[<column_definition>] |column_nameAScomputed_column_expression }[, n] |[WITH CHECK | WITH NOCHECK]ADD {}[, n] ...
select*from test where 基本工资<10000or 基本工资>20000#查询表中基本工资低于10000或高于20000的员工所有信息 select*from test where 基本工资in(8000,9000,10000)#查询表中工资为8000,9000,和10000的员工所有信息。 select*from test where ×××号 like'66%'#查询test表中×××号以66开头的员工所有信息。
2、ALTER TABLE 具体语法: ALTERTABLEtable_name {[ALTER COLUMN <column_name> {[<schema of new data type>].<new_data_type>[(precision [,scale])]max|<xmlschemacollection>[COLLATE <collation_name>][NULL | NOT NULL]|[{ADD | DROP} ROWGUIDCOL]|PERSISTED}]|ADD<columnname><data_type>[[DEFA...
Can I have a primary key as a non-unique column Can I pass parameter to an ALTER DATABASE command Can I prevent deadlock during concurrent delete Can I print to file using T- SQL Can I sort an SQL table? Can I sort row without order by clause Can I UPDATE, then INSERT if no ...
AlterCertificateStatementKind AlterColumnAlterFullTextIndexAction AlterColumnEncryptionKeyStatement AlterCreateEndpointStatementBase AlterCreateServiceStatementBase AlterCredentialStatement AlterCryptographicProviderStatement AlterDatabaseAddFileGroupStatement AlterDatabaseAddFileStatement AlterDatabaseAuditSpecificati...
alter table t alter column c1 bigint 邏輯讀取0,LOB 實體讀 --僅回傳如下的訊息,沒有 I/O --命令已順利完成. alter table t alter column c2 nvarchar(200) 範例程式碼 4-34:更動既有資料表的資料行類型時,小心是否導致大量 I/O 01 02 03 4-2 05 06 07 資料類型 14 這一點有人在大聲疾呼,...
ALTERTABLEtable_nameALTERCOLUMNcolumn_name [type_name] [NULL|NOTNULL] [COLLATEcollation_name] example: This example demonstrates how to change an existing table column’s nullability and data type.The Gender column in the HumanResources.Employeetable is originally NOT NULL and the original data typ...
–1. IDENTIY 列不能为空,不能设默认值,创建后不能使用ALTER TABLE TableName ALTER COLUMN修改,每张表只能有一个自增列 –2. 查看当前值:SELECT IDENT_CURRENT(‘TableName’), — 查看增量值:SELECT IDENT_INCR(‘TableName’) — 查看原始种子值:SELECT IDENT_SEED(‘TableName’),起始值, TRUNCATE TABL...
AlterCertificateStatementKind AlterColumnAlterFullTextIndexAction AlterColumnEncryptionKeyStatement AlterCreateEndpointStatementBase AlterCreateServiceStatementBase AlterCredentialStatement AlterCryptographicProviderStatement AlterDatabaseAddFileGroupStatement AlterDatabaseAddFileStatement AlterDatabaseAuditSpe...
where =object_id('表名') and a.xtype=b.xtype 把“表名”替换成你要查看字段类型的表名,比如你要查看sysobjects表的各字段类型那么就是 select as [column], as type from syscolumns a,systypes b where =object_id('sysobjects') and a.xtype=b.xtype ...