Where am i going wrong with this IF Exist Else

Question

Where am i going wrong with this IF Exist Else

DHeath

SSCertifiable

Points: 5200
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March 23, 2018 at 6:22 am

#410357

Can someone please let me know where i am going wrong in this code snippet...its when i try to place the set @Loop = @Loop + 1.
Basically trying to go thru a list and if the table already exists then to skip it and move to the next.
All comments and help super appreciated. Thanks
DECLARE @Loop INT,
   @cmd VARCHAR(MAX),
   @rc INT,
        @TB VARCHAR(130)
-- I am creates a new temporary table with a sequential ID (and no gaps),
-- so I can loop by it:
use AS400Schema
SELECT ROWID = IDENTITY(INT,1,1),TABLENAME
into #Tables
FROM [AS400Schema].[dbo].[schemanames] where TableSchema = 'AECF' and TableType = 'Base Table'
ORDER BY TABLENAME
SET @rc = @@ROWCOUNT
SET @Loop = 1
-- Looping on table names, dropping and recreating each:
WHILE @Loop <= @rc
BEGIN
SELECT @TB = TABLENAME FROM #Tables WHERE ROWID = @Loop
SET @cmd = '' /*Set @cmd = 'use test3 IF EXISTS (SELECT 1 FROM sys.objects WHERE Type = ''U''' +
      'AND name = ''' + @TB + ''') DROP TABLE [' + @TB + '];' +
      'SELECT * INTO dbo.[' + @TB + '] ' +
      'FROM [AS400Schema].[dbo].[schemanames]' */
--Print @cmd

/****** My issue is in here someplace ****/
SELECT @cmd = 'use AEC_BPCS IF EXISTS (SELECT 1 FROM sys.objects WHERE Type = ''U''' +
      'AND name = ''' + @TB + ''') BEGIN SET '@Loop = @Loop + 1' END' + ' ELSE '+
      'SELECT * INTO dbo.[' + @TB + '] ' +
      'FROM [AS400].[RCHASE5C].[AECF].[' + @TB + ']'

    Print @cmd
EXEC (@cmd)
SET @Loop = @Loop + 1
END
DROP TABLE #Tables
DHeath

Viewing 11 posts - 1 through 10 (of 10 total)

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Gail Shaw SSC Guru Points: 1004504 More actions · Answer 1

What error is being thrown, or what is it doing that it's not supposed to?

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

We walk in the dark places no others will enter
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DHeath SSCertifiable Points: 5200 More actions · Answer 2

Thanks for the reply... The error is
Msg 102, Level 15, State 1, Line 1
Incorrect syntax near '@Loop = @Loop + 1'.

If there is another way to loop thru this i am okay with it but i know its VERY close to being there..

DHeath

Bert-701015 SSCommitted Points: 1615 More actions · Answer 3

Remove the single quote around @Loop = @Loop + 1

AND name = ''' + @TB + ''') BEGIN SET '@Loop = @Loop + 1' END' + ' ELSE '+

DHeath SSCertifiable Points: 5200 More actions · Answer 4

Thank you for your reply

When i remove the single quote that is around the @Loop = @Loop + 1 i still get the same error. which is
Msg 102, Level 15, State 1, Line 39
Incorrect syntax near '@Loop'.

I can make the code run PERFECTLY as long as i am NOT using the ELSE but i need to use that so that i can pick up where it left off (table constraint error) and NOT re-import a few hundred thousand entries and 2+ hours time. hahaha

DHeath

Bert-701015 SSCommitted Points: 1615 More actions · Answer 5

So your code now looks like this?:
' + 'FROM [AS400].[RCHASE5C].[AECF].[' + @TB + ']'"]

I'm not getting a syntax error with it.

Bert-701015 SSCommitted Points: 1615 More actions · Answer 6

Actually, I think the problem is your dynamic SQL doesn't recognize the variable (@Loop)
' + 'FROM [AS400].[RCHASE5C].[AECF].[' + @TB + '] END' "]

DHeath SSCertifiable Points: 5200 More actions · Answer 7

Thanks so much for the help... it compiles and runs but returns this error
Msg 137, Level 15, State 2, Line 1
Must declare the scalar variable "@Loop".

Which i dont understand because its declared at the very top as my very first declaration

Thanks for helping.

DHeath

Neil Burton SSC-Insane Points: 23009 More actions · Answer 8

You also need to declare the @Loop variable in your dynamic SQL because it executes a s separate batch* and so any previously declared variables will not be available. Try changing the affected part to this:

SELECT @cmd = 'use AEC_BPCS DECLARE @loop INT IF EXISTS (SELECT 1 FROM sys.objects WHERE Type = ''U''' + 'AND name = ''' + @TB + ''') BEGIN SET @Loop = @Loop + 1 END' + ' ELSE '+ 'SELECT * INTO dbo.[' + @TB + '] ' + 'FROM [AS400].[RCHASE5C].[AECF].[' + @TB + ']' Print @cmd

* I'll stand to be corrected on the details here but the point is the same.

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—Charles Babbage, Passages from the Life of a Philosopher

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DHeath SSCertifiable Points: 5200 More actions · Answer 9

SUCCESS!!!!!!!!

Thank to all... Greatly appreciated on all the assistance from anyone that replied or read the post

Currently the code is running and like i said hopefully i have my logic correct as to where it will only populate new tables and not ones that are already in existence.

Thanks again

DHeath

@Taps SSC Eights! Points: 879 More actions · Answer 10

Just wanted to point out that the @loop increment inside the dynamic SQL will not carry through to @loop increment outside the dynamic SQL
Again it depends how you are actually using this variable . Pointing it out as I see you are incrementing @loop twice

Thanks