Most likely, SQL Server will resolve the OR and the Union options the same way: Split the query in two and then merge the results together.

Look at the execution plans...

Clarification needed: Are you loading 2 files at the same time, or are you loading 1 file that might be in a different format different times?

I.e.: Do you have an...

Sean Lange (6/7/2016)

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Jeff Moden (6/7/2016)

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I think it's a great question. It shows whether or not you...

mcfarlandparkway (6/9/2016)

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TY Champion,

These variables...

Do your users know that you're planning on doing that? It sounds seriously drastic.

If you really want to do this, you can find this data in sys.dm_exec_requests. https://msdn.microsoft.com/en-us/library/ms177648.aspx

The most common cause of "sudden slowdown of what used to be fast" is a change of data volume.

The second most common is hardware degradation (RAID rebuild, etc.).

After that, it's...

It's hard to help you write a query with this little to go on.

Any chance you could include the table structure (as a "Create Table" statement, not just text), and...

The logic I see is a cascading calculation from some row in a table with an "F" in it, up to a value from another table.

If the variables aren't used...

What kind of testing? In what environment?

It looks like you want to use 1 of 2 end date values. 1 from the query, 1 from a variable.

Any rules? Like use the lowest value? ...

The subject you're asking about is called "data hygiene". It's about things like duplicates, unexpected NULL values, out-of-expected-range values, and a whole lot of other similar issues.

It takes a...

Sounds about right.

In SSIS, you'd set it to redirect error rows.

In T-SQL, you have to write your own error-handling routine.

Have you tried replacing the computed column with a static column?

Does the data in this table get changed frequently through direct connections? That's the main reason to use computed...

You can drop and recreate foreign key constraints if you want to load data in the main table first. This can create problems with untrusted constraints. It can...

Multiple possible reasons:

1. They don't know better and don't have a good reason

2. If the length variation falls in certain patterns, fixed-width stores more efficiently because of the 2-byte variable-length...