问题
I would like this to be the ultimate discussion on how to check if a table exists in SQL Server 2000/2005 using SQL Statements.
When you Google for the answer, you get so many different answers. Is there an official/backward and forward compatible way of doing it?
Here are two possible ways of doing it. Which one among the two is the standard/best way of doing it?
First way:
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;
Second way:
IF OBJECT_ID (N\'mytablename\', N\'U\') IS NOT NULL
SELECT 1 AS res ELSE SELECT 0 AS res;
MySQL provides the simple
SHOW TABLES LIKE \'%tablename%\';
statement. I am looking for something similar.
回答1:
For queries like this it is always best to use an INFORMATION_SCHEMA view. These views are (mostly) standard across many different databases and rarely change from version to version.
To check if a table exists use:
IF (EXISTS (SELECT *
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = 'TheSchema'
AND TABLE_NAME = 'TheTable'))
BEGIN
--Do Stuff
END
回答2:
Also note that if for any reason you need to check for a temporary table you can do this:
if OBJECT_ID('tempdb..#test') is not null
--- temp table exists
回答3:
We always use the OBJECT_ID style for as long as I remember
IF OBJECT_ID('*objectName*', 'U') IS NOT NULL
回答4:
Please see the below approaches,
Approach 1: Using INFORMATION_SCHEMA.TABLES view
We can write a query like below to check if a Customers Table exists in the current database.
IF EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = N'Customers')
BEGIN
PRINT 'Table Exists'
END
Approach 2: Using OBJECT_ID() function
We can use OBJECT_ID() function like below to check if a Customers Table exists in the current database.
IF OBJECT_ID(N'dbo.Customers', N'U') IS NOT NULL
BEGIN
PRINT 'Table Exists'
END
Approach 3: Using sys.Objects Catalog View
We can use the Sys.Objects catalog view to check the existence of the Table as shown below:
IF EXISTS(SELECT 1 FROM sys.Objects WHERE Object_id = OBJECT_ID(N'dbo.Customers') AND Type = N'U')
BEGIN
PRINT 'Table Exists'
END
Approach 4: Using sys.Tables Catalog View
We can use the Sys.Tables catalog view to check the existence of the Table as shown below:
IF EXISTS(SELECT 1 FROM sys.Tables WHERE Name = N'Customers' AND Type = N'U')
BEGIN
PRINT 'Table Exists'
END
Approach 5: Avoid Using sys.sysobjects System table
We should avoid using sys.sysobjects System Table directly, direct access to it will be deprecated in some future versions of the Sql Server. As per Microsoft BOL link, Microsoft is suggesting to use the catalog views sys.objects/sys.tables instead of sys.sysobjects system table directly.
IF EXISTS(SELECT name FROM sys.sysobjects WHERE Name = N'Customers' AND xtype = N'U')
BEGIN
PRINT 'Table Exists'
END
referred from: http://sqlhints.com/2014/04/13/how-to-check-if-a-table-exists-in-sql-server/
回答5:
Looking for a table on a different database:
if exists (select * from MyOtherDatabase.sys.tables where name = 'MyTable')
print 'Exists'
回答6:
Just wanted to mention one situation where it would probably be a little easier to use the OBJECT_ID method. The INFORMATION_SCHEMA views are objects under each database-
The information schema views are defined in a special schema named INFORMATION_SCHEMA. This schema is contained in each database.
https://msdn.microsoft.com/en-us/library/ms186778.aspx
Therefore all tables you access using
IF EXISTS (SELECT 1
FROM [database].INFORMATION_SCHEMA.TABLES
WHERE TABLE_TYPE='BASE TABLE'
AND TABLE_NAME='mytablename')
SELECT 1 AS res ELSE SELECT 0 AS res;
will only reflect what is in [database]. If you wanted to check if tables in another database exist, without dynamically changing the [database] each time, OBJECT_ID will let you do this out of the box. Ex-
IF OBJECT_ID (N'db1.schema.table1', N'U') IS NOT NULL
SELECT 1 AS res ELSE SELECT 0 AS res;
works just as well as
IF OBJECT_ID (N'db2.schema.table1', N'U') IS NOT NULL
SELECT 1 AS res ELSE SELECT 0 AS res;
SQL SERVER 2016 Edit:
Starting with 2016, Microsoft simplified the ability to check for non-existent objects prior to dropping, by adding the if exists keywords to drop statements. For example,
drop table if exists mytablename
will do the same thing as OBJECT_ID / INFORMATION_SCHEMA wrappers, in 1 line of code.
https://blogs.msdn.microsoft.com/sqlserverstorageengine/2015/11/03/drop-if-exists-new-thing-in-sql-server-2016/
回答7:
IF OBJECT_ID('mytablename') IS NOT NULL
回答8:
Using the Information Schema is the SQL Standard way to do it, so it should be used by all databases that support it.
回答9:
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
Here in the above code, the table name is Mapping_APCToFANavigator.
回答10:
If you need to work on different databases:
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
回答11:
I know it is an old question but I have found this possibility if you plan to call it often.
create procedure Table_Exists
@tbl varchar(50)
as
return (select count(*) from sysobjects where type = 'U' and name = @tbl)
go
回答12:
Just adding here, for the benefit of developers and fellow DBAs
a script that receives @Tablename as a parameter
(which may or may not contain the schemaname) and returns the info below if the schema.table exists:
the_name object_id the_schema the_table the_type
[Facts].[FactBackOrder] 758293761 Facts FactBackOrder Table
I produced this script to be used inside other scripts every time I need to test whether or not a table or view exists, and when it does, get its object_id to be used for other purposes.
It raises an error when either you passed an empty string, wrong schema name or wrong table name.
this could be inside a procedure and return -1 for example.
As an example, I have a table called "Facts.FactBackOrder" in one of my Data Warehouse databases.
This is how I achieved this:
PRINT 'THE SERVER IS ' + @@SERVERNAME
--select db_name()
PRINT 'THE DATABASE IS ' + db_NAME()
PRINT ''
GO
SET NOCOUNT ON
GO
--===================================================================================
-- @TableName is the parameter
-- the object we want to deal with (it might be an indexed view or a table)
-- the schema might or might not be specified
-- when not specified it is DBO
--===================================================================================
DECLARE @TableName SYSNAME
SELECT @TableName = 'Facts.FactBackOrder'
--===================================================================================
--===================================================================================
DECLARE @Schema SYSNAME
DECLARE @I INT
DECLARE @Z INT
SELECT @TableName = LTRIM(RTRIM(@TableName))
SELECT @Z = LEN(@TableName)
IF (@Z = 0) BEGIN
RAISERROR('Invalid @Tablename passed.',16,1)
END
SELECT @I = CHARINDEX('.',@TableName )
--SELECT @TableName ,@I
IF @I > 0 BEGIN
--===================================================================================
-- a schema and table name have been passed
-- example Facts.FactBackOrder
-- @Schema = Fact
-- @TableName = FactBackOrder
--===================================================================================
SELECT @Schema = SUBSTRING(@TABLENAME,1,@I-1)
SELECT @TableName = SUBSTRING(@TABLENAME,@I+1,@Z-@I)
END
ELSE BEGIN
--===================================================================================
-- just a table name have been passed
-- so the schema will be dbo
-- example Orders
-- @Schema = dbo
-- @TableName = Orders
--===================================================================================
SELECT @Schema = 'DBO'
END
--===================================================================================
-- Check whether the @SchemaName is valid in the current database
--===================================================================================
IF NOT EXISTS ( SELECT * FROM INFORMATION_SCHEMA.SCHEMATA K WHERE K.[SCHEMA_NAME] = @Schema ) BEGIN
RAISERROR('Invalid Schema Name.',16,1)
END
--SELECT @Schema as [@Schema]
-- ,@TableName as [@TableName]
DECLARE @R1 TABLE (
THE_NAME SYSNAME
,THE_SCHEMA SYSNAME
,THE_TABLE SYSNAME
,OBJECT_ID INT
,THE_TYPE SYSNAME
,PRIMARY KEY CLUSTERED (THE_SCHEMA,THE_NAME)
)
;WITH RADHE_01 AS (
SELECT QUOTENAME(SCHEMA_NAME(O.schema_id)) + '.' + QUOTENAME(O.NAME) AS [the_name]
,the_schema=SCHEMA_NAME(O.schema_id)
,the_table=O.NAME
,object_id =o.object_id
,[the_type]= CASE WHEN O.TYPE = 'U' THEN 'Table' ELSE 'View' END
from sys.objects O
where O.is_ms_shipped = 0
AND O.TYPE IN ('U','V')
)
INSERT INTO @R1 (
THE_NAME
,THE_SCHEMA
,THE_TABLE
,OBJECT_ID
,THE_TYPE
)
SELECT the_name
,the_schema
,the_table
,object_id
,the_type
FROM RADHE_01
WHERE the_schema = @Schema
AND the_table = @TableName
IF (@@ROWCOUNT = 0) BEGIN
RAISERROR('Invalid Table Name.',16,1)
END
ELSE BEGIN
SELECT THE_NAME
,THE_SCHEMA
,THE_TABLE
,OBJECT_ID
,THE_TYPE
FROM @R1
END
回答13:
In SQL Server 2000 you can try:
IF EXISTS(SELECT 1 FROM sysobjects WHERE type = 'U' and name = 'MYTABLENAME')
BEGIN
SELECT 1 AS 'res'
END
回答14:
IF EXISTS
(
SELECT *
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = 'PutSchemaHere'
AND
TABLE_NAME = 'PutTableNameHere'
)
回答15:
Something important to know for anybody who hasn't found their solution yet: SQL server != MYSQL. If you want to do it with MYSQL, it is quite simple
$sql = "SELECT 1 FROM `db_name`.`table_name` LIMIT 1;";
$result = mysql_query($sql);
if( $result == false )
echo "table DOES NOT EXIST";
else
echo "table exists";
Posting this here because it's the top hit at Google.
回答16:
IF EXISTS ( SELECT * FROM dbo.sysobjects WHERE id = OBJECT_ID(N'dbo.TableName') AND OBJECTPROPERTY(id, N'IsUserTable') = 1 )
BEGIN
SELECT * FROM dbo.TableName;
END
GO
回答17:
You can use this :
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
回答18:
select name from SysObjects where xType='U' and name like '%xxx%' order by name
回答19:
-- -- create procedure to check if a table exists
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 ;
-- -- how to use : check if table migrations exists
CALL checkIfTableExists('muDbName', 'migrations', @output);
回答20:
IF EXISTS (
SELECT *
FROM INFORMATION_SCHEMA.TABLES
WHERE
TABLE_CATALOG = 'Database Name' and
TABLE_NAME = 'Table Name' and
TABLE_SCHEMA = 'Schema Name') -- Database and Schema name in where statement can be deleted
BEGIN
--TABLE EXISTS
END
ELSE BEGIN
--TABLE DOES NOT EXISTS
END
回答21:
If anyone is trying to do this same thing in linq to sql (or especially linqpad) turn on option to include system tables and views and do this code:
let oSchema = sys.Schemas.FirstOrDefault(s=>s.Name==a.schema )
where oSchema !=null
let o=oSchema!=null?sys.Objects.FirstOrDefault (o => o.Name==a.item && o.Schema_id==oSchema.Schema_id):null
where o!=null
given that you have an object with the name in a property called item, and the schema in a property called schema where the source variable name is a
回答22:
If this is to be the 'ultimate' discussion, then it should be noted that Larry Leonard's script can query a remote server as well if the servers are linked.
if exists (select * from REMOTE_SERVER.MyOtherDatabase.sys.tables where name = 'MyTable')
print 'Exists'
回答23:
I've had some problems either with selecting from INFORMATIONAL_SCHEME and OBJECT_ID. I don't know if it's an issue of ODBC driver or something.. Queries from SQL management studio, both, were okay.
Here is the solution:
SELECT COUNT(*) FROM <yourTableNameHere>
So, if the query fails, there is, probably, no such table in the database (or you don't have access permissions to it).
The check is done by comparing the value (integer in my case) returned by SQL executor which deals with ODBC driver..
if (sqlexec(conectionHandle, 'SELECT COUNT(*) FROM myTable') == -1) {
// myTable doesn't exist..
}
回答24:
You can use bellow code
IF (OBJECT_ID('TableName') IS NOT NULL )
BEGIN
PRINT 'Table Exists'
END
ELSE
BEGIN
PRINT 'Table NOT Exists'
END
Or
IF (EXISTS (SELECT * FROM sys.tables WHERE NAME = 'TableName'))
BEGIN
PRINT 'Table Exists'
END
ELSE
BEGIN
PRINT 'Table NOT Exists'
END
回答25:
Run this query to check if the table exists in the database:
IF(SELECT TABLE_NAME from INFORMATION_SCHEMA.TABLES where TABLE_NAME = 'YourTableName') IS NOT NULL
PRINT 'Table Exists';
回答26:
consider in one database you have a table t1. you want to run script on other Database like - if t1 exist then do nothing else create t1. To do this open visual studio and do the following:
Right click on t1, then Script table as, then DROP and Create To, then New Query Editor
you will find your desired query. But before executing that script don't forget to comment out the drop statement in the query as you don't want to create new one if there is already one.
Thanks
来源：https://stackoverflow.com/questions/167576/check-if-table-exists-in-sql-server