How do I escape the underscore character?
I am writing something like the following where clause and want to be able to find actual entries with _d at the end.
Where Username Like '%_d'
T-SQL Reference for LIKE:
You can use the wildcard pattern matching characters as literal characters. To use a wildcard character as a literal character, enclose the wildcard character in brackets. The following table shows several examples of using the LIKE keyword and the [ ] wildcard characters.
For your case:
... LIKE '%[_]d'
Obviously #Lasse solution is right, but there's another way to solve your problem: T-SQL operator LIKE defines the optional ESCAPE clause, that lets you declare a character which will escape the next character into the pattern.
For your case, the following WHERE clauses are equivalent:
WHERE username LIKE '%[_]d'; -- #Lasse solution
WHERE username LIKE '%$_d' ESCAPE '$';
WHERE username LIKE '%^_d' ESCAPE '^';
These solutions totally make sense. Unfortunately, neither worked for me as expected. Instead of trying to hassle with it, I went with a work around:
select *
from information_schema.columns
where replace(table_name,'_','!') not like '%!%'
order by table_name
I had a similar issue using like pattern '%_%' did not work - as the question indicates :-)
Using '%\_%' did not work either as this first \ is interpreted "before the like".
Using '%\\_%' works. The \\ (double backslash) is first converted to single \ (backslash) and then used in the like pattern.
Adding [ ] did the job for me
like '%[\\_]%'
This worked for me, just use the escape
'%\_%'
None of these worked for me in SSIS v18.0, so I would up doing something like this:
WHERE CHARINDEX('_', thingyoursearching) < 1..where I am trying to ignore strings with an underscore in them. If you want to find things that have an underscore, just flip it around:
WHERE CHARINDEX('_', thingyoursearching) > 0
Adding to Gerardo Lima's answer, I was having problems when trying to use backslash as my escape character for the ESCAPE clause. This caused issues:
SELECT * FROM table WHERE email LIKE '%#%\_%' ESCAPE '\'
It was resolved by switching to an exclamation point. This worked:
SELECT * FROM table WHERE email LIKE '%#%!_%' ESCAPE '!'
Related
I am trying to find a certain set of characters in a column from a datatable. I have tried the pattern that seems more logical to me (right below) but it doesn't seem to be doing the job. What I wish to achieve is a pattern where I have something like '["5"]', basically with: square brackets, quotation marks, any integer number, quotation marks, square brackets. The output I am getting is just empty, and I can't seem to undersand why. Besides this, I would like to update the records that do not follow this pattern to follow it. Does anyone have a solution for this?
To give you some context, here is the test table:
I want to achive only the last three records.
Here is what I have tried:
SELECT ToJsonTestValue
FROM Test
WHERE ToJsonTestValue LIKE '["%"]'
and
UPDATE dbo.Test
SET ToJsonTestValue = '["'+ToJsonTestValue+'"]'
WHERE ToJsonTestValue LIKE '#';
You have a couple of problem here. Firstly you have the square brackets, which needs escaping. Then you also use % which is a multi character wildcard, however, it appears that you want a single character. It also appears that that character can only be an integer, so you might want to be more specific. Either of these should give you the result you want:
--Using single character wildcard:
SELECT *
FROM (VALUES('["1"]'),('["["1"]"]'))V(S)
WHERE V.S LIKE '[[]"_"[\]]' ESCAPE '\';
--Specifically requiring int:
SELECT *
FROM (VALUES('["1"]'),('["["1"]"]'))V(S)
WHERE V.S LIKE '[[]"[0-9]"[\]]' ESCAPE '\';
In SQL Server, how to search special characters like square brackets?
I have tried using code below to search .
select *
from dbo.Content
where title like '%\[TESTING(TEST)(\[]%' escape '\'.
I need to manually put backslash in front of all square bracket in order to get the result. Does anyone know what query/function can use to query all kind of data especially special characters.
To search for [ just write [[]
Any special character can be escaped this way. So % will be [%]
Or maybe this suits more your question
REPLACE(REPLACE(REPLACE(#myString, '[', '[[]'), '_', '[_]'), '%', '[%]')
How to escape a string for use with the LIKE operator in SQL Server?
Instead of checking for Special character we can check for alphanumeric and then have NOT (!) to get the row where title has special characters. (WHERE title LIKE '%[^a-z0-9 .]%' )
I am trying to filter items with a stored procedure using like. The column is a varchar(15). The items I am trying to filter have square brackets in the name.
For example: WC[R]S123456.
If I do a LIKE 'WC[R]S123456' it will not return anything.
I found some information on using the ESCAPE keyword with LIKE, but how can I use it to treat the square brackets as a regular string?
LIKE 'WC[[]R]S123456'
or
LIKE 'WC\[R]S123456' ESCAPE '\'
Should work.
Let's say you want to match the literal its[brac]et.
You don't need to escape the ] as it has special meaning only when it is paired with [.
Therefore escaping [ suffices to solve the problem. You can escape [ by replacing it with [[].
I needed to exclude names that started with an underscore from a query, so I ended up with this:
WHERE b.[name] not like '\_%' escape '\' -- use \ as the escape character
Here is what I actually used:
like 'WC![R]S123456' ESCAPE '!'
The ESCAPE keyword is used if you need to search for special characters like % and _, which are normally wild cards. If you specify ESCAPE, SQL will search literally for the characters % and _.
Here's a good article with some more examples
SELECT columns FROM table WHERE
column LIKE '%[[]SQL Server Driver]%'
-- or
SELECT columns FROM table WHERE
column LIKE '%\[SQL Server Driver]%' ESCAPE '\'
According to documentation:
You can use the wildcard pattern matching characters as literal
characters. To use a wildcard character as a literal character,
enclose the wildcard character in brackets.
You need to escape these three characters %_[:
'5%' LIKE '5[%]' -- true
'5$' LIKE '5[%]' -- false
'foo_bar' LIKE 'foo[_]bar' -- true
'foo$bar' LIKE 'foo[_]bar' -- false
'foo[bar' LIKE 'foo[[]bar' -- true
'foo]bar' LIKE 'foo]bar' -- true
If you would need to escape special characters like '_' (underscore), as it was in my case, and you are not willing/not able to define an ESCAPE clause, you may wish to enclose the special character with square brackets '[' and ']'.
This explains the meaning of the "weird" string '[[]' - it just embraces the '[' character with square brackets, effectively escaping it.
My use case was to specify the name of a stored procedure with underscores in it as a filter criteria for the Profiler. So I've put string '%name[_]of[_]a[_]stored[_]procedure%' in a TextData LIKE field and it gave me trace results I wanted to achieve.
Here is a good example from the documentation:
LIKE (Transact-SQL) - Using Wildcard Characters As Literals
There is a problem in that while
LIKE 'WC[[]R]S123456'
and
LIKE 'WC\[R]S123456' ESCAPE '\'
both work for SQL Server, neither work for Oracle.
It seems that there isn't any ISO/IEC 9075 way to recognize a pattern involving a left brace.
Instead of '\' or another character on the keyboard, you can also use special characters that aren't on the keyboard. Depending o your use case this might be necessary, if you don't want user input to accidentally be used as an escape character.
Use the following.
For user input to search as it is, use escape, in that it will require the following replacement for all special characters (the below covers all of SQL Server).
Here a single quote, "'" ,is not taken as it does not affect the like clause as it is a matter of string concatenation.
The "-" & "^" & "]" replace is not required as we are escaping "[".
String FormattedString = "UserString".Replace("ð","ðð").Replace("_", "ð_").Replace("%", "ð%").Replace("[", "ð[");
Then, in SQL Query it should be as following. (In parameterised query, the string can be added with patterns after the above replacement).
To search an exact string.
like 'FormattedString' ESCAPE 'ð'
To search start with a string:
like '%FormattedString' ESCAPE 'ð'
To search end with a string:
like 'FormattedString%' ESCAPE 'ð'
To search containing with a string:
like '%FormattedString%' ESCAPE 'ð'
And so on for other pattern matching. But direct user input needs to be formatted as mentioned above.
I have a where clause like the below example:
WHERE (subject LIKE 'chef%') AND (dep LIKE 'psy%%')
What is the difference using 1 or 2 percent signs? I know what one means (wild card), but not what the second adds in functionality.
That query is likely a typo; putting a double % does nothing in the example you have given as there are no non-wildcard characters between the two %'s.
If you wanted to search for an actual % character you can use escaping.
Usage of double '%' is mostly for specifying there are no wildcards present between them.however it is also used for using actual '%' in searchquery which is called escaping.
using '%' escaping looks like
SELECT name FROM emp
WHERE id LIKE '%\%%' ESCAPE '\'
for more details on escaping Escaping
I am trying to filter items with a stored procedure using like. The column is a varchar(15). The items I am trying to filter have square brackets in the name.
For example: WC[R]S123456.
If I do a LIKE 'WC[R]S123456' it will not return anything.
I found some information on using the ESCAPE keyword with LIKE, but how can I use it to treat the square brackets as a regular string?
LIKE 'WC[[]R]S123456'
or
LIKE 'WC\[R]S123456' ESCAPE '\'
Should work.
Let's say you want to match the literal its[brac]et.
You don't need to escape the ] as it has special meaning only when it is paired with [.
Therefore escaping [ suffices to solve the problem. You can escape [ by replacing it with [[].
I needed to exclude names that started with an underscore from a query, so I ended up with this:
WHERE b.[name] not like '\_%' escape '\' -- use \ as the escape character
Here is what I actually used:
like 'WC![R]S123456' ESCAPE '!'
The ESCAPE keyword is used if you need to search for special characters like % and _, which are normally wild cards. If you specify ESCAPE, SQL will search literally for the characters % and _.
Here's a good article with some more examples
SELECT columns FROM table WHERE
column LIKE '%[[]SQL Server Driver]%'
-- or
SELECT columns FROM table WHERE
column LIKE '%\[SQL Server Driver]%' ESCAPE '\'
According to documentation:
You can use the wildcard pattern matching characters as literal
characters. To use a wildcard character as a literal character,
enclose the wildcard character in brackets.
You need to escape these three characters %_[:
'5%' LIKE '5[%]' -- true
'5$' LIKE '5[%]' -- false
'foo_bar' LIKE 'foo[_]bar' -- true
'foo$bar' LIKE 'foo[_]bar' -- false
'foo[bar' LIKE 'foo[[]bar' -- true
'foo]bar' LIKE 'foo]bar' -- true
If you would need to escape special characters like '_' (underscore), as it was in my case, and you are not willing/not able to define an ESCAPE clause, you may wish to enclose the special character with square brackets '[' and ']'.
This explains the meaning of the "weird" string '[[]' - it just embraces the '[' character with square brackets, effectively escaping it.
My use case was to specify the name of a stored procedure with underscores in it as a filter criteria for the Profiler. So I've put string '%name[_]of[_]a[_]stored[_]procedure%' in a TextData LIKE field and it gave me trace results I wanted to achieve.
Here is a good example from the documentation:
LIKE (Transact-SQL) - Using Wildcard Characters As Literals
There is a problem in that while
LIKE 'WC[[]R]S123456'
and
LIKE 'WC\[R]S123456' ESCAPE '\'
both work for SQL Server, neither work for Oracle.
It seems that there isn't any ISO/IEC 9075 way to recognize a pattern involving a left brace.
Instead of '\' or another character on the keyboard, you can also use special characters that aren't on the keyboard. Depending o your use case this might be necessary, if you don't want user input to accidentally be used as an escape character.
Use the following.
For user input to search as it is, use escape, in that it will require the following replacement for all special characters (the below covers all of SQL Server).
Here a single quote, "'" ,is not taken as it does not affect the like clause as it is a matter of string concatenation.
The "-" & "^" & "]" replace is not required as we are escaping "[".
String FormattedString = "UserString".Replace("ð","ðð").Replace("_", "ð_").Replace("%", "ð%").Replace("[", "ð[");
Then, in SQL Query it should be as following. (In parameterised query, the string can be added with patterns after the above replacement).
To search an exact string.
like 'FormattedString' ESCAPE 'ð'
To search start with a string:
like '%FormattedString' ESCAPE 'ð'
To search end with a string:
like 'FormattedString%' ESCAPE 'ð'
To search containing with a string:
like '%FormattedString%' ESCAPE 'ð'
And so on for other pattern matching. But direct user input needs to be formatted as mentioned above.