I have a SQL script that populates a temp column and then drops the column at the end of the script. The first time it runs, it works fine because the column exists, then it gets dropped. The script breaks the 2nd time because the column no longer exists, even though the IF statement ensures that it won't run again. How do I get around SQL checking for this field?
IF EXISTS (SELECT name FROM syscolumns
WHERE name = 'COLUMN_THAT_NO_LONGER_EXISTS')
BEGIN
INSERT INTO TABLE1
(
COLUMN_THAT_NO_LONGER_EXISTS,
COLUMN_B,
COLUMN_C
)
SELECT 1,2,3 FROM TABLE2
ALTER TABLE TABLE1 DROP COLUMN COLUMN_THAT_NO_LONGER_EXISTS
END
I had a similar problem once and got round it by building all the queries as strings and executing them using the Exec() call. That way the queries (selects, inserts or whatever) don't get parsed till they are executed.
It wasn't pretty or elegant though.
e.g
exec('INSERT INTO TABLE1(COLUMN_THAT_NO_LONGER_EXISTS,COLUMN_B,COLUMN_C) SELECT 1,2,3 FROM TABLE2')
Are you checking the column isnt on another table ? If not you probably to check the table too see if statement below.
If you are already doing that is it running a in a single transaction and not picking up the that dropped column has gone ?
IF Not EXISTS (SELECT name FROM sys.columns
WHERE name = 'COLUMN_THAT_NO_LONGER_EXISTS' and Object_Name(object_id) = 'Table1')
Created a quick script program for this; can you confirm this matches what you are trying to do because in SQL 2007 at least this isnt returning an error. If i create the table and run through with teh alter table to add colc it works; if i then run the if / insert that works even after dropping the table.
create table tblTests
(
TestID int identity (1,1),
TestColA int null,
TestColB int null
)
go -- Ran this on its own
insert into tblTests (TestColA, TestColB)
Select 1,2
go 10
-- Insert some initial data
alter table tblTests
add TestColC Int
go -- alter the table to add new column
-- Run this with column and then after it has removed it
IF EXISTS (SELECT name FROM sys.columns a
WHERE name = 'TestColC' AND
OBJECT_NAME(object_id) = 'tblTests')
Begin
insert into tblTests (TestColA, TestColB, testcolc)
select 1,2,3
alter table tblTests
drop column TestColC
End
Related
I want to write sql script that should check if column exists in the table, and then remove the column if previous statement is true. The database I use is Sybase ASE, and this is the code that I tried to use:
IF EXISTS (SELECT 1 FROM syscolumns WHERE id = object_id('users') AND name = 'maiden_name')
BEGIN
ALTER TABLE security DROP maiden_name
END
The code above executed successfully first time I run it. The second time I goth the error:
Invalid column name 'maiden_name'
If column does not exist the ALTER TABLE block of code shouldn't run. Is there a way to achieve this is Sybase? Thank you.
You can use dynamic SQL:
IF EXISTS (SELECT 1 FROM syscolumns WHERE id = object_id('users') AND name = 'maiden_name')
BEGIN
EXEC('ALTER TABLE security DROP maiden_name')
END;
The problem is that the parser is trying to parse the ALTER during the compilation phase, and it gets an error if the column does not exist.
I'm creating a table using multiple subselects. So I am getting data from multiple places within one SQL Database.
What I want is to 1. Set the above as a table itself and 2. create a new table using the above results.
So I will call the above [table1].
I just want to know how to set this as a (temporary) table so i can then start to add new script which I can use to the data I have now received in my new table to display.
You might be looking for SELECT INTO clause:
Select (select Project.Number from Project where Project.ProjectID = PurchaseOrder.ProjectID) as [Project],
PurchaseOrder.Number,
(Select GoodsReceipt.ReceiptNumber from GoodReceipt where GoodsReceipt.ReferenceID = PurchaseOrder.PurchaseOrderID) as [GReceipt]
INTO TABLE1
From PurchaseOrder
You can just write SELECT YOURCOLUMNS INTO #TEMP FROM XXXXX
And then you can start a new script by writing
Note: You new script has to been in the same session when you make use of temp tables
DROP TABLE IF EXISTS DBO.TEST --This only works on SQL Server 2016
/* Drop Table */
IF OBJECT_ID('dbo.Test', 'U') IS NOT NULL
DROP TABLE dbo.Test;
Create Table dbo.TEST (
COLUMNS DATATYPE NULL
)
Insert into DBO.TEST
SELECT * FROM #TEMP
DROP TABLE #TEMP
Hi I have a temporary table in which I am trying to insert records based on a where condition but it throws an error that it already exists.
I have tried to change the names but that is not the issue as the temporary tables are delete when the session ends.
I think I am writing the query right.
SELECT [Name]
INTO #TEMP_REJECT
FROM #TEMP_VALIDATION
WHERE Name = #Name
I am trying to insert #TEMP_REJECT FROM #TEMP_VALIDATION
Error message
"There is already an object named '#TEMP_REJECT' in the database."
Please suggest.
Thank you for your help.
R
SQL Server won't tell you that a table doesn't exist if it doesn't.
I suggest that you add
IF OBJECT_ID('tempdb..#TEMP_REJECT') IS NOT NULL
DROP TABLE #TEMP_REJECT
in front of your select statement. This guarantees that the temp table won't exist when the select is executed.
So your statement becomes
IF OBJECT_ID('tempdb..#TEMP_REJECT') IS NOT NULL
DROP TABLE #TEMP_REJECT
SELECT [Name]
INTO #TEMP_REJECT
FROM #TEMP_VALIDATION
WHERE Name = #Name
This answer will help you :
https://stackoverflow.com/a/8560644/3635715
To make short : SELECT INTO creates table then insert records.
INSERT INTO only insert the records.
So in your case, since #TEMP_REJECT already exists, SELECT INTO is rejected because it cannot create the table again, so you have to use INSERT INTO after first SELECT INTO.
IF OBJECT_ID('tempdb..#TEMP_REJECT') IS NOT NULL
BEGIN
INSERT INTO #TEMP_REJECT
SELECT [Name]
FROM #TEMP_VALIDATION
WHERE Name = #Name
END
ELSE
BEGIN
SELECT [Name]
INTO #TEMP_REJECT
FROM #TEMP_VALIDATION
WHERE Name = #Name
END
References :
INTO Clause
INSERT Clause
Try checking before inserting
if object_id('tempdb..#TEMP_REJECT') is not null
drop table #TEMP_REJECT
SELECT [Name]
INTO #TEMP_REJECT
FROM #TEMP_VALIDATION
WHERE Name = #Name
if SQL says,there is temp table,there must be a table prior to your insert
I've noticed that I get the same error when I am working consecutively through the same SQL Server tab/file.
For example, I have a large SQL file that I use to execute a series of updates using temp tables. When I execute it consecutively, it errors out complaining that my #tempTable already exists (even if I use a "if this table exists, drop it" statement as DeanOC describes).
Exiting out of the file/tab between consecutive runs resolves the issue.
If this poses an issue for your use case, I'd suggest bundling your statements in a stored proc and implementing DeanOC's drop logic therein.
So far i was using
IF OBJECT_ID(''tempdb..#tempTable'') IS NOT NULL -- dropping the temp table
DROP TABLE #tempTable
Is there a way in which I could use the same statement for a table which is not a temp one?
Tried like this and it didn't work:
IF OBJECT_ID(''myOwnDb.dbo.myTable'') IS NOT NULL -- dropping the table
DROP TABLE dbo.myTable
Strings in MS SQL server should be enclosed in single quotes.
So neither OBJECT_ID(''myOwnDb.dbo.myTable'') nor OBJECT_ID("myOwnDb.dbo.myTable") will work.
But OBJECT_ID('myOwnDb.dbo.myTable') will work perfectly.
In addition to what other users have suggested wrt Object_ID which is fine, you can explore below method to detect if table exist or not using INFORMATION_SCHEMA
IF EXISTS (SELECT * FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME = N'Your Table Name')
BEGIN
Drop table <tablename>
END
The reason it did not work is because you have the extra quotes instead of single quotes.
i.e. You should be doing this:
IF OBJECT_ID('myOwnDb.dbo.myTable') IS NOT NULL -- dropping the table
DROP TABLE dbo.myTable
However, note that when you actually drop the table. You aren't even referencing the database. So you can just do:
IF OBJECT_ID('dbo.myTable') IS NOT NULL -- dropping the table
DROP TABLE dbo.myTable
Unless you are calling this command from another database. Then you will need to include the database name in the DROP TABLE command as well.
If I try to execute the following code, I get the errors
Msg 207, Level 16, State 1, Line 3 Invalid column name 'Another'. Msg
207, Level 16, State 1, Line 4 Invalid column name 'Another'.
even though the predicate for both IF statements always evaluates to false.
CREATE TABLE #Foo (Bar INT)
GO
IF (1=0)
BEGIN
SELECT Another FROM #Foo
END
GO
IF (1=0)
BEGIN
ALTER TABLE #Foo ADD Another INT
SELECT Another FROM #Foo
END
GO
DROP TABLE #Foo
This is probably over-simplified for the sake of the example; in reality what I need to do is select the values from a column, but only if the column exists. If it doesn't exist, I don't care about it. In the problem that drove me to ask this question, my predicate was along the lines of EXISTS (SELECT * FROM sys.columns WHERE object_id = #ID AND name = #Name). Is there a way to achieve this without resorting to my arch-enemy Dynamic SQL? I understand that my SQL must always be well-formed (i.e. conform to grammar) - even within a block that's never executed - but I'm flabbergasted that I'm also being forced to make it semantically correct too!
EDIT:
Though I'm not sure the code below adds much to the code above, it's a further example of the problem. In this scenario, I only want to set the value of Definitely (which definitely exists as a column) with the value from Maybe (which maybe exists as a column) if Maybe exists.
IF EXISTS (SELECT * FROM sys.columns WHERE object_id = OBJECT_ID('dbo.TableName', 'U') AND name = 'Maybe')
BEGIN
UPDATE dbo.TableName SET Definitely = Maybe
END
SQL Server doesn't execute line by line. It isn't procedural like .net or Java code. So there is no "non-executed block"
The batch is compiled in one go. At this point, the column doesn't exist but it knows the table will be. Table does not have a column called "Another". Fail.
Exactly as expected.
Now, what is the real problem you are trying to solve?
Some options:
2 tables or one table with both columns
use Stored procedures to decouple scope
not use temp tables (maybe not needed; it could be your procedural thinking...)
dynamic SQL (from Mitch's deleted answer)
Edit, after comment;
Why not hide schema changes behind a view, rather than changing all code to work with columns that may/may not be there?
You can use EXEC to handle it. It's not really dynamic SQL if the code never actually changes.
For example:
CREATE TABLE dbo.Test (definitely INT NOT NULL)
INSERT INTO dbo.Test (definitely) VALUES (1), (2), (3)
IF EXISTS (SELECT *
FROM sys.columns
WHERE object_id = OBJECT_ID('dbo.Test', 'U') AND
name = 'Maybe')
BEGIN
EXEC('UPDATE dbo.Test SET definitely = maybe')
END
SELECT * FROM dbo.Test
ALTER TABLE dbo.Test ADD maybe INT NOT NULL DEFAULT 999
IF EXISTS (SELECT *
FROM sys.columns
WHERE object_id = OBJECT_ID('dbo.Test', 'U') AND
name = 'Maybe')
BEGIN
EXEC('UPDATE dbo.Test SET definitely = maybe')
END
SELECT * FROM dbo.Test
DROP TABLE dbo.Test
You can also try Martin Smith's "Workaround" using a non-existing table to get "deferred name resolution" for columns.
I had the same issue.
We are creating a script for all changes for years and this is the first time that we have this issue.
I've tried all your answers and didn't find the issue.
In my case it was because of temporary table within the script that I'm using also within a stored procedure, although every sentence has go.
I've found that if I'm adding if exists with drop to the temporary table after the script is using the temporary table, it is working correctly.
Best regards,
Chen
Derived from the answer by #gbn.
What i did to solve the issue was to use 'GO' between the ALTER query and the query that uses the column added by ALTER. This will make the 2 queries to be run as separate batches thereby ensuring your 'Another' column is there before the SELECT query.