我希望这是关于如何使用SQL语句检查SQL Server 2000/2005中是否存在表的最终讨论。
这里有两种可能的方法。哪一种是做这件事的标准/最佳方式?
第一个方法:
IF EXISTS (SELECT 1
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_TYPE='BASE TABLE'
AND TABLE_NAME='mytablename')
SELECT 1 AS res ELSE SELECT 0 AS res;
第二种方式:
IF OBJECT_ID (N'mytablename', N'U') IS NOT NULL
SELECT 1 AS res ELSE SELECT 0 AS res;
MySQL提供简单的
SHOW TABLES LIKE '%tablename%';
声明。我在找类似的东西。
当前回答
-- -- create过程检查表是否存在
DELIMITER $$
DROP PROCEDURE IF EXISTS `checkIfTableExists`;
CREATE PROCEDURE checkIfTableExists(
IN databaseName CHAR(255),
IN tableName CHAR(255),
OUT boolExistsOrNot CHAR(40)
)
BEGIN
SELECT count(*) INTO boolExistsOrNot FROM information_schema.TABLES
WHERE (TABLE_SCHEMA = databaseName)
AND (TABLE_NAME = tableName);
END $$
DELIMITER ;
-- --如何使用:检查表迁移是否存在
CALL checkIfTableExists('muDbName', 'migrations', @output);
其他回答
在不同的数据库中查找表:
if exists (select * from MyOtherDatabase.sys.tables where name = 'MyTable')
print 'Exists'
你可以用这个:
IF OBJECT_ID (N'dbo.T', N'U') IS NOT NULL
BEGIN
print 'deleted table';
drop table t
END
else
begin
print 'table not found'
end
Create table t (id int identity(1,1) not null, name varchar(30) not null, lastname varchar(25) null)
insert into t( name, lastname) values('john','doe');
insert into t( name, lastname) values('rose',NULL);
Select * from t
1 john doe
2 rose NULL
-- clean
drop table t
IF EXISTS
(
SELECT *
FROM sys.objects
WHERE object_id = OBJECT_ID(N'[dbo].[Mapping_APCToFANavigator]')
AND
type in (N'U')
)
BEGIN
-- Do whatever you need to here.
END
在上面的代码中，表名是mapping_apctofannavigator。
如果你需要使用不同的数据库:
DECLARE @Catalog VARCHAR(255)
SET @Catalog = 'MyDatabase'
DECLARE @Schema VARCHAR(255)
SET @Schema = 'dbo'
DECLARE @Table VARCHAR(255)
SET @Table = 'MyTable'
IF (EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_CATALOG = @Catalog
AND TABLE_SCHEMA = @Schema
AND TABLE_NAME = @Table))
BEGIN
--do stuff
END
我认为下面的查询是可行的:
IF EXISTS (select * from sys.tables
WHERE name='mytablename' )
BEGIN
print 'table exists in the database'
END
