CODEWITHSUNDEEP
sqlsql-server-2008if-statement
Jmh2013
Jmh2013

Reputation: 2777

SQL IF statement is being ignored

I have a long script and I like to be able to just run the whole file when I need to and not worry about if parts of it have already ran. But the script below is giving me problems. For some reason it is getting past the IF statement even when the columns 'EntityID' and 'EntityType' do not exist, in which case it should not get through the IF statement. Can someone tell me what is wrong? 

IF EXISTS (SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'Notes' AND COLUMN_NAME IN ('EntityId', 'EntityType'))
BEGIN
    BEGIN TRANSACTION
        --Delete notes where EntityType and EntityID are both NULL
        DELETE FROM [dbo].[Notes]
        WHERE [EntityId] = NULL 
        AND [EntityType] = NULL
        --Delete notes where the corresponding contact or account has been deleted.
        OR [ID] IN (9788, 10684, 10393, 10718, 10719)

        --Populate new columns with all existing data
        UPDATE [dbo].[Notes]
        SET [AccountId] = [EntityId]
        WHERE [EntityType] = 1

        UPDATE [dbo].[Notes]
        SET [ContactId] = [EntityId]
        WHERE [EntityType] = 2

        --Delete EntityId and EntityType columns from the Notes table
        ALTER TABLE [dbo].[Notes]
        DROP COLUMN [EntityId], [EntityType]
    COMMIT
END
GO

The script for the table

CREATE TABLE [dbo].[Notes](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [AnnotationID] [uniqueidentifier] NULL,
    [CreatedBy] [int] NULL,
    [CreatedDate] [datetime] NULL,
    [NoteText] [ntext] NULL,
    [OriginalAnnotationID] [uniqueidentifier] NULL,
    [Active] [bit] NULL,
    [ContactId] [int] NULL,
    [AccountId] [int] NULL,
 CONSTRAINT [PK_Notes] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

GO

ALTER TABLE [dbo].[Notes]  WITH CHECK ADD  CONSTRAINT [FK_Account_ID] FOREIGN KEY([AccountId])
REFERENCES [dbo].[Account] ([ID])
GO

ALTER TABLE [dbo].[Notes] CHECK CONSTRAINT [FK_Account_ID]
GO

ALTER TABLE [dbo].[Notes]  WITH CHECK ADD  CONSTRAINT [FK_ContactId_ID] FOREIGN KEY([ContactId])
REFERENCES [dbo].[Contact] ([ID])
GO

ALTER TABLE [dbo].[Notes] CHECK CONSTRAINT [FK_ContactId_ID]
GO

The errors:

Msg 207, Level 16, State 1, Line 6
Invalid column name 'EntityId'.
Msg 207, Level 16, State 1, Line 7
Invalid column name 'EntityType'.
Msg 207, Level 16, State 1, Line 12
Invalid column name 'EntityType'.
Msg 207, Level 16, State 1, Line 16
Invalid column name 'EntityType'.

Upvotes: 1

Views: 2283

Answers (2)

Aaron Bertrand
Aaron Bertrand

Reputation: 280262

Martin was definitely onto something. The stuff inside the IF is being treated by the parser at parse time and ignoring whether your IF will pan out. This is the same reason you can't do:

IF 1 = 1
  CREATE TABLE #x(a INT);
ELSE
  CREATE TABLE #x(b INT);

One workaround would be to use dynamic SQL:

IF EXISTS ...
BEGIN
  BEGIN TRANSACTION;

  DECLARE @sql NVARCHAR(MAX);

  SET @sql = N'
        DELETE FROM [dbo].[Notes]
        WHERE [EntityId] IS NULL 
        AND [EntityType] IS NULL
        --Delete notes where the corresponding contact or account has been deleted.
        OR [ID] IN (9788, 10684, 10393, 10718, 10719)

        --Populate new columns with all existing data
        UPDATE [dbo].[Notes]
        SET [AccountId] = [EntityId]
        WHERE [EntityType] = 1

        UPDATE [dbo].[Notes]
        SET [ContactId] = [EntityId]
        WHERE [EntityType] = 2

        --Delete EntityId and EntityType columns from the Notes table
        ALTER TABLE [dbo].[Notes]
        DROP COLUMN [EntityId], [EntityType]';

    EXEC sp_executesql @sql;

    COMMIT TRANSACTION;
END

But you still should be sure that both columns are there.

Upvotes: 3

Gordon Linoff
Gordon Linoff

Reputation: 1269553

I suspect the problem is that one of the columns exist but not both. Try the following:

IF 2 = (SELECT count(*) FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'Notes' AND COLUMN_NAME IN ('EntityId', 'EntityType'))

Upvotes: 0

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