Question

I’m trying to use the REPLACE function in SQL and I am having problems with trying to append a string to the end of the current contents of a column.

set ActualRegex = REPLACE(ActualRegex, ActualRegex, ActualRegex + '[\d\D]*') 

These strings will be used for Regex checks in a C# program, but that’s not particularly relevant to the problem.

When I try running this query, i end up getting an error message

Msg 8152, Level 16, State 14, Line 1
String or binary data would be truncated.
The statement has been terminated.

I’ve checked the field sizes, and the resulting strings will not be nearly long enough to exceed the size of the field (varchar(512)). At biggest they might be 50 characters long unless something strange is happening that I’m unaware about.

Thanks in advance for any help!

EDIT: Here’s the full query

update [Registration].[dbo].[MigrationOfTagTypes] set ActualRegex = 
REPLACE(ActualRegex, ActualRegex, ActualRegex + '[\d\D]*') 
where Regex != '' and Regex like '%\%' escape '\'

EDIT: Actually, I figured it out and turns out I was just being stupid and overlooking something small. Apparently these fields were filled with lots of empty whitespace appended onto the end of the strings, so appending to that would result in breaking the size constraint. Thanks for all the help!

Answer 1

Msg 8152, Level 16, State 14, Line 1
String or binary data would be truncated.
The statement has been terminated.

There are two reasons for this:

1. Your varchar column is not large enough. Appending 7 characters to an existing 10 into a varchar(15) column won’t work
2. Your column is defined as char (why?!). Char columns have implicit trailing spaces, so if you add ‘ABC’ to a char(10) field containing ‘XYZ’, it actually ends up as ‘XYZ ABC’ (13) which is longer than char(10).

In the 2nd case, i.e. char columns, use RTRIM

update [Registration].[dbo].[MigrationOfTagTypes] set ActualRegex = 
RTRIM(REPLACE(ActualRegex, ActualRegex, ActualRegex + '[\d\D]*')) 
where Regex != '' and Regex like '%\%' escape '\'

Note: using replace like this allows 'ABCxxxABC' to become 'ABC[\d\D]*xxxABC[\d\D]*'

If you simply wanted to append to the end of the column, then you would use

update [Registration].[dbo].[MigrationOfTagTypes]
set ActualRegex = RTRIM(ActualRegex) + '[\d\D]*'
where Regex != '' and Regex like '%\%' escape '\'