How do I check the end of a particular string using SQL pattern matching?

I am trying to use sql p开发者_StackOverflowattern matching to check if a string value is in the correct format.

The string code should have the correct format of:

alphanumericvalue.alphanumericvalue

Therefore, the following are valid codes:

D0030.2190
C0052.1925
A0025.2013

And the following are invalid codes:

D0030
.2190
C0052.
A0025.2013.
A0025.2013.2013

So far I have the following SQL IF clause to check that the string is correct:

IF @vchAccountNumber LIKE '_%._%[^.]'

I believe that the "_%" part checks for 1 or more characters. Therefore, this statement checks for one or more characters, followed by a "." character, followed by one or more characters and checking that the final character is not a ".".

It seems that this would work for all combinations except for the following format which the IF clause allows as a valid code:

A0025.2013.2013

I'm having trouble correcting this IF clause to allow it to treat this format as incorrect. Can anybody help me to correct this?

Thank you.

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This stackoverflow question mentions using word-boundaries: [[:<:]] and [[:>:]] for whole word matches. You might be able to use this since you don't have spaces in your code.

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This is ANSI SQL solution

This LIKE expression will find any pattern not alphanumeric.alphanumeric. So NOT LIKE find only this that match as you wish:

IF @vchAccountNumber NOT LIKE '%[^A-Z0-9].[^A-Z0-9]%'

However, based on your examples, you can use this...

LIKE '[A-Z][0-9][0-9][0-9][0-9].[0-9][0-9][0-9][0-9]'

...or one like this if you 5 alphas, dot, 4 alphas

LIKE '[A-Z0-9][A-Z0-9][A-Z0-9][A-Z0-9][A-Z0-9].[A-Z0-9][A-Z0-9][A-Z0-9][A-Z0-9]'

The 2nd one is slightly more obvious for fixed length values. The 1st one is slighty less intuitive but works with variable length code either side of the dot.

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