CASE WHEN “I need to learn more T-SQL” THEN GoogleTheResult() END

One of my favorite recent discoveries in my SQL Server work recently, is the awesome T-SQL “CASE…WHEN…THEN” statement. I can’t describe how much I love this thing.

It’s pretty simple really:


SELECT
CASE
WHEN fruit = 'apples' THEN 'not oranges'
WHEN fruit = 'oranges' THEN 'not apples'
ELSE 'neither apples nor oranges'
END AS fruit
FROM fruits

As can be expected, for every row where the column is set to “apples”, this will output “not oranges”. For those with the value “oranges”, it will output “not apples”, and of course, any other value (such as “bananas”) would output “neither apples nor oranges”.

To make things more interesting, you can combine the comparison portion (i.e. x = y) with any WHERE based comparisons, such as:

  • X IS NULL
  • X IN (value1,value2)
  • X >= 7
  • X =1 AND >=27
  • X+Y>27 OR ISNULL(Z,0) = 0
Using the comparison, you can even output different columns as the result. I.e.
  • WHEN columnA is null THEN columnB
  • WHEN columnA+columnB > 27 THEN columnB/(SELECT MAX(columnA) FROM TABLE)

Thanks Google. I really love this statement, it’s allowed for some pretty funky complex T-SQL scripts recently, and made my life alot easier!

Backing up all SQL Server user databases to file

The ultimate lazy backup script. I wasn’t feeling to selective about which databases to backup, and I figured, it’d be best to back them all up, even that testing database I¬†occasionally¬†use for data import/export. Never know when I might need it again…

This sits inside a SQL Server Agent job, and runs nightly. Simple enough really.

All works as expected on SQL Server 2012.

DECLARE @Database varchar(max)
DECLARE @path varchar(max)
SET @path = concat(N'D:\BACKUP\',convert(varchar,getdate(),112),' ALL DATABASES BACKUP.bak')
DECLARE my_cursor CURSOR FOR
select name from sys.databases where database_id>4
OPEN my_cursor
FETCH NEXT FROM my_cursor
INTO @Database
WHILE @@FETCH_STATUS = 0
BEGIN
BACKUP DATABASE @Database TO DISK = @path WITH NOFORMAT, NOINIT, NAME = N'SQL Server all user databases backup', SKIP, NOREWIND, NOUNLOAD, STATS = 10
FETCH NEXT FROM my_cursor
INTO @Database
END
CLOSE my_cursor
DEALLOCATE my_cursor

I’m sure there’s a better way to do this, but there doesn’t appear to be a column in the sys.databases table which denotes a database as a system or user database. Instead, I’ve used the WHERE database_id > 4 – which removes master, model, msdb, and tempdb from the backup.