Beginning Microsoft SQL Server 2008 ... - S3 Tech Training

Out of the condition from inner condition, but still
part of first block
END --First block of code ends here
ELSE
BEGIN
Statement that executes if expression is FALSE
Additional statements
...
...
Still going with statements from FALSE expression
END
Chapter 11: Writing Scripts and Batches
Notice our ability to nest blocks of code. In each case, the inner blocks are considered to be part of the
outer block of code. I have never heard of there being a limit to how many levels deep you can nest your
BEGIN...END blocks, but I would suggest that you minimize them. There are definitely practical limits
to how deep you can keep them readable — even if you are particularly careful about the formatting of
your code.
Just to put this notion into play, let’s make yet another modification to table creation. This time, we’re
going to provide an informational message regardless of whether the table was created or not.
-- This time we’re adding a check to see if the table DOES already exist
-- We’ll remove it if it does so that the rest of our example can test the
-- IF condition. Just remove this first IF EXISTS block if you want to test
-- the ELSE condition below again.
IF EXISTS (
SELECT s.name AS SchemaName, t.name AS TableName
FROM sys.schemas s
JOIN sys.tables t
ON s.schema_id = t.schema_id
WHERE s.name = ‘dbo’
AND t.name = ‘OurIFTest’
)
DROP TABLE OurIFTest;
-- Now we’re run our conditional CREATE statement
IF NOT EXISTS (
SELECT s.name AS SchemaName, t.name AS TableName
FROM sys.schemas s
JOIN sys.tables t
ON s.schema_id = t.schema_id
WHERE s.name = ‘dbo’
AND t.name = ‘OurIFTest’
)
BEGIN
PRINT ‘Table dbo.OurIFTest not found.’;
PRINT ‘CREATING: Table dbo.OurIFTest’;
CREATE TABLE OurIFTest(
Col1 int PRIMARY KEY
);
END
ELSE
PRINT ‘WARNING: Skipping CREATE as table already exists’;
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