does the table CAF have a column called Currency_ID?

Do you want to find the corresponding Rate in the Currency table, based on the Currency_ID, and assign the Euro_Value column...

>>INNER JOIN dbo.Table_2 T2 (nolock)

>>ON T1.column = T2.column

>>AND ( T2.ID = @ID OR @ID = 0)

Explain the logic of what you are trying to acheive here. Never use an...

Explain (in "pseudo-code", not T-SQL) what you are trying to do.

Faulty logic that does not work, is all you are showing us.

Impossible it is, then, to determine your...

>>see the policycode=001 .... when it gets endorse, it gets changed to 001/02

no! Two columns you should have. Policy Code is "001", and never changes. Other column,...

very clever ... Approaching the problem from a different point of view, you are! MAX() you may use, instead of SUM, should you desire.

Beware of EXISTS() .... unless contained...

hm...

If natural key arises from data, use that you should! A table of US States ... abbreviation, a good key makes, not a "StateID" identity, hm? Too may...

>>Do I have to take any further action (like somehow linking these two columns in the database -- dunno how in mysql)? (My app does this well though already.)

hmm ......

your primary key should be artistID/productID (a composite primary key).

if not, a unique constraint you have on those two columns, I hope!

One UDF per summary, write you must. Dynamic SQL, a UDF cannot use. Nor can you, in the manner in which you tried. SELECT * FROM @TableName,...

oops.. yes, Yoda had it backwards. Long weekend, indeed!

Either way, unless a convincing reason is given, done this should not be!

Very nice, David. The force is strong with you!

Grouping on many non-primary key columns, usually indicates time for subquery (derived table).

Vertical partioning, this is, hm?  Horizontal = moving attributes (i.e., columns) to a new table, not moving rows.  edit: Yoda a little tired from the weekend!

Why do you feel you must do...

Why store flag or use CASE expression for each column? if at least one single column changes for a particular row, update all columns you can. By definition, changed...

hmmm ... Yes, as Celko points out -- fundamental problem with your JOIN, there is. Select Max or Min or some other paritcular value from the joined table, you...

Fair enough, and very well put!