Sql query syntax help

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I have wrote a select query but which one is correct i am little but confused below the both queries

SQL

IF @IDStatus IS NOT NULL
		IF EXISTS(SELECT 0 FROM tabBlobItem AS tbi		
				WHERE tbi.IDBlobItem = @IDBlobItem
				AND tbi.UrlRandom = @UrlRandom
				AND tbi.IDStatus = @IDStatus)
			BEGIN 		          
				SET @ReturnValue = 1
			END
			ELSE
			BEGIN
				SET @ReturnValue = 0
			END 
	
	Print @ReturnValue

SQL

IF @IDStatus IS NOT NULL
BEGIN --This i have added above this i have not written
		IF EXISTS(SELECT 0 FROM tabBlobItem AS tbi		
				WHERE tbi.IDBlobItem = @IDBlobItem
				AND tbi.UrlRandom = @UrlRandom
				AND tbi.IDStatus = @IDStatus)
			BEGIN 		          
				SET @ReturnValue = 1
			END
			ELSE
			BEGIN
				SET @ReturnValue = 0
			END 
END 
	
	Print @ReturnValue

What I have tried:

I have tried both but need to know which one is correct

Posted 28-Jan-19 4:13am

Rakib Ahmed

Updated 28-Jan-19 5:06am

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CHill60 · Accepted Answer · 2019-01-28T04:43:00

The are both equally correct.

IF statements in SQL can only handle a single statement or statement block. You can handle lots of statements by enclosing them in BEGIN. . . END - which defines a single statement (block). Reference IF...ELSE (Transact-SQL) - SQL Server | Microsoft Docs[^]

You could have also use

SQL

IF @IDStatus IS NOT NULL
		IF EXISTS(SELECT 0 FROM tabBlobItem AS tbi		
				WHERE tbi.IDBlobItem = @IDBlobItem
				AND tbi.UrlRandom = @UrlRandom
				AND tbi.IDStatus = @IDStatus)
			SET @ReturnValue = 1
			ELSE
			SET @ReturnValue = 0
	
	Print @ReturnValue

In my opinion the use of BEGIN . . .END helps to clarify your intent

OriginalGriff · Accepted Answer · 2019-01-28T05:07:00

I'd have to agree with CHill60 - they are the same, but the first version is more maintainable because it's obvious what is in- and out-side the IF.

In the same way that C, C++, or C# uses curly brackets for start and end of a block, it's safer and more maintainable to use them even if they aren't needed:

SQL

if (condition)
   BEGIN
   if (otherCondition)
      BEGIN      
      statement;
      END
   else
      BEGIN
      statement;
      END
   END
SELECT ...

It's obvious that the SELECT if not conditional.
It's also obvious if you leave them out:

SQL

if (condition)
   if (otherCondition)
      statement;
   else
      statement;
SELECT ...

But ... SQL doesn't enforce indentation, it could all be on the same line:

SQL

if (condition) BEGIN if (otherCondition) BEGIN statement; END else BEGIN statement; END END SELECT ...

That's hard to read, but pretty obvious what is going on.
But take 'em out:

SQL

if (condition) if (otherCondition) statement; else statement; SELECT ...

And work that out at your leisure!

Adding them (and indenting your code) means that when you have to change it it's a lot easier to work out what is going on.

Sql query syntax help

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