If I deliberately store trailing spaces in a VARCHAR
column, how can I force SQL Server to see the data as mismatch?
SELECT 'foo' WHERE 'bar' = 'bar '
I have tried:
SELECT 'foo' WHERE LEN('bar') = LEN('bar ')
One method I've seen floated is to append a specific character to the end of every string then strip it back out for my presentation... but this seems pretty silly.
Is there a method I've overlooked?
I've noticed that it does not apply to leading spaces so perhaps I run a function which inverts the character order before the compare.... problem is that this makes the query unSARGable....
SQL Server TRIM() Function The TRIM() function removes the space character OR other specified characters from the start or end of a string. By default, the TRIM() function removes leading and trailing spaces from a string.
Also, from the support page on How SQL Server Compares Strings with Trailing Spaces: SQL Server follows the ANSI/ISO SQL-92 specification on how to compare strings with spaces. The ANSI standard requires padding for the character strings used in comparisons so that their lengths match before comparing them.
Takeaway: According to SQL Server, an identifier with trailing spaces is considered equivalent to the same identifier with those spaces removed.
From the docs on LEN (Transact-SQL):
Returns the number of characters of the specified string expression, excluding trailing blanks. To return the number of bytes used to represent an expression, use the
DATALENGTH
function
Also, from the support page on How SQL Server Compares Strings with Trailing Spaces:
SQL Server follows the ANSI/ISO SQL-92 specification on how to compare strings with spaces. The ANSI standard requires padding for the character strings used in comparisons so that their lengths match before comparing them.
Update: I deleted my code using LIKE
(which does not pad spaces during comparison) and DATALENGTH()
since they are not foolproof for comparing strings
This has also been asked in a lot of other places as well for other solutions:
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