It means that you have a primary key on the table, a constraint that forces all values in a column to be unique.

Since you tried to insert duplicate values...

Insert into Service (GroupNo,ServiceCode,ServiceName,SystemNo,Upload,ControlNo)

SELECT 6,ServiceCode,ServiceName,SystemNo,Upload,ControlNo

FROM Service

WHERE GroupNo=1

The select takes all the records in Service that have a GroupNo of 1 (Where...)

The constant in the select clause (SELECT 6, ...) means...

Why? Sum ignores nulls. It will add up non-null values. The isnull around the sum is just incase the entire column is null or there are no records. That's the...

Yes, and you have to join it as meny times as there are levels in the nesting.

Just a warning. It's not going to run fast. I'd recomend that you...

I think this will work. I've only done it 3 levels deep, but the principle's there and you should be able to extend it to as many levels as you...

Hmmm, that's going to be one messy query.

Let me think about this....

Sum ignores nulls. If you sum a column that contains nulls, you'll get the total of the non-null values and a warning saying null values were eliminated due to aggregation.

The...

Ok, a bit better.

so...

z  a

x  z

y  x

if I ask x, I'll get a

if I ask y, I'll also get a

Is that right?

Is there any limit on how deep...

How do you define 'latest'? Do you have a date or timestamp somewhere in there or some other way to order the records?

If the table has

y  a

x  a

x  y

a  c

y ...

Can you post the table structure please, columns, constraints, current indexes. also if possible, the update statements that run.

Thanks

Why two columns? Tis a much better design to have a single column that stores the current datetime.

Getdate retuns the current date and time to an accuracy of 3 ms....

Remove builtin\Administrators from the sysadmin role. Make sure that you have another admin account before you do that. Make sure that the sa login has a strong password.

It won't stop him from...

I wouldn't personally think more than about 10-20% from just splitting the files. Now if you're moving to faster disks as well, you'll get an increase from that as well.

We're...

It depends on whether the data required for the join is in memory or on disk. If both tables are in memory, then there will be no gain (because no...

I forgot to mention, we've currently got three filegroups, clustered indexes in 1, nonclusters in the second and some of the tables text images in the third and we're looking...