From now, every time you'll write a joined query, you'll think to Elthon JOIN.

In confidence, I prefer Freddy Mercury e his band The QUEEN.

No doubt: TERMINATOR & friends.

Also the DISTINCT clause and the GROUP BY perform an implicit ORDER BY for all cols, but "IMPLICIT" is...

Without the ORDER BY clause, you can not predict the order of rows.

NULL, 1 and 1, NULL are both possible.

In the future release of sqlserver or in another DBMS, the...

It always is correct WITH THIS SET OF DATA. Try adding a couple of zero(e)s at the end of each of the 3 numbers and watch "Msg 8115, Level...

Main rule is never to use float, because of unwanted effetcs:

Here the version with decimal. It always is correct.

DECLARE @SumA float, @SumB float

DECLARE @MyFloat1 float, @MyFloat2 float, @MyFloat3 float

DECLARE @MyTable...

That's true:

DECLARE @SumA float, @SumB float

DECLARE @MyFloat1 float, @MyFloat2 float, @MyFloat3 float

DECLARE @MyTable table

(

ID int primary key identity,

NumA float,

NumB float

)

SET @MyFloat1 = 10000000000020000

SET @MyFloat2 = -10000000000010000

SET @MyFloat3 = 1

INSERT INTO...

Good idea! But just for few rows result set. Else it takes too long to run if put the result set in join with another table.

Another thing never said: when creating temp table is better adding the "collate" to char/varchar/text etc. cause of different collate in tempdb e the current db.:w00t:

I couldn't believe that someone need to use "datename(m,join_date) like '%a%'" to extract rows of Jan, Feb, March, April, May, Aug. :w00t:

Double single quota!

In this case, I prefer dynamic sql and add only conditions I need. Performance are granted more than complex and useless conditions. 🙂