Using wildcards - sql

Can anyone help me out with this-
There is a column in the database as "TEXT".
This column hold some string value.
I want to search any row that is having '%' in this column .
For eg how will i search for a row having value 'Vivek%123' in the column TEXT

In sql there is something known as an escape character, basically if you use this character it will be ignored and the character right behind it will be used as a literal instead of a wildcard in the case of %
WHERE Text LIKE '%!%%'
ESCAPE '!'
The above sql statement will allow you to search for any string containing a percentage character '%' so it could find anything in the format of
string%string

You must escape the % character
WHERE COL1 LIKE 'Vivek#%123' ESCAPE '#' ;

Related

Semicolon in LIKE is not working for SQL server 2017

I have a query like this which is not retrieving the values from DB table even if the required value exist there.
Here's the query, which return zero rows:
Select * from SitePanel_FieldValue WHere SiteFieldIdfk =111
And SiteFieldvalue like '%!##$%&*()-_=+{}|:"<>?[]\;'',./%'
Following is the value in the table:
'!##$%&*()-_=+{}|:"<>?[]\;'',./'
When I run the query without ";" it is returning the value.
Can any one help me in figuring this out?
Thanks
Ritu
You are using multiple characters which are reserved when using LIKE statement.
i.e. %, _, []
Use the escape character clause (where I have used backtick to treat special characters as regular) such as
Select * from SitePanel_FieldValue WHere SiteFieldIdfk =111
And SiteFieldvalue like '%!##$`%&*()-`_=+{}|:"<>?`[`]\;'',./%' escape '`'
The value in your table is:
!##$%&*()-_=+{};; :"<>?[]\;'',./
And the one in the like is:
(!##$%&*()-_=+{};;
Starting with ( it will never match, also you should scape the percent (%) in the middle of the string like this:
Select *
FROM SitePanel_FieldValue
WHERE SiteFieldIdfk =111
AND SiteFieldvalue like '%!##$\%&*()-_=+{};;%' ESCAPE '\'
The problem is your brackets ([]), it has nothing to do with semicolons. If we remove the brackets, the above works:
SELECT CASE WHEN '!##$%&*()-_=+{}|:"<>?\;'',./' LIKE '%!##$%&*()-_=+{}|:"<>?\;'',./%' THEN 1 END AS WithoutBrackets,
CASE WHEN '!##$%&*()-_=+{}|:"<>?[]\;'',./' LIKE '%!##$%&*()-_=+{}|:"<>?[]\;'',./%' THEN 1 END AS WithBrackets
Notice that WithoutBrackets returns 1, where as WithBrackets returns NULL.
Brackets in a LIKE are to denote a pattern. For example SomeExpress LIKE '[ABC]' would match the characters, A, B, and C. If you are going to include special characters, you need to ESCAPE them. You have both brackets, a percent sign (%) and an underscore (_) you need to escape. You don't need to escape the hyphen (-), as it doesn't appear in a pattern (for example [A-Z]). I choose to use a backtick as the ESCAPE character, as it doesn't appear in your string, and demonstrate with a CASE expression again:
SELECT CASE WHEN '!##$%&*()-_=+{}|:"<>?[]\;'',./' LIKE '%!##$`%&*()-`_=+{}|:"<>?`[`]\;'',./%' ESCAPE '`' THEN 1 END;
If you wanted to use a backslash (\ ), which many do, you would need to also escape the backslash in your string:
SELECT CASE WHEN '!##$\%&*()-_=+{}|:"<>?[]\;'',./' LIKE '%!##$%&*()-\_=+{}|:"<>?\[\]\\;'',./%' ESCAPE '\' THEN 1 END;
db<>fiddle
I think the issue is actually with the backslash. This is an escape character and so if you want it to be included, you have to put it in twice.
Select * from SitePanel_FieldValue WHere SiteFieldIdfk =111
And SiteFieldvalue like '%!##$%&*()-_=+{}|:"<>?[]\\;'',./%'

Matching literal percent in h2/postgres?

I have the following value in a db column:
some%thing
I'm using h2 and postgres, but can't figure out why this query, where I have escaped the % to perform a literal search, is not matching the row highlighted?:
LIKE 'some\%thing'
Because 'value' is a character string literal and not the name of your column. You need to use double quotes instead.
"value" LIKE 'some\%hing'
One option is to use regular expressions:
where value ~ '%'
LIKE also supports an explicit escape character:
where value like '%$%%' escape '$'
Or the default one, \.

How to escape '|' in SQL Server or T-SQL Query?

SELECT *
FROM performance_table
WHERE ad_group like '%|%'
I have no idea on how to escape the Pipe operator here.
You don't need to escape | in T-SQL as it has no special meaning inside like. However, if for example you would like to find texts containing % character, what you're looking for is:
SELECT *
FROM performance_table
WHERE ad_group like '%#%%' escape '#'
where escape defines escape character.
The pipe character does not need to be escaped.
Your query will find all records that contain a pipe character in the ad_group column.
When used inside a string literal ('|'), the character is not treated as an operator. Its function as an operator is bitwise OR, as for example in
select 8|3
will be 11.

Search an Oracle clob for special characters that are not escaped

Is it possible to run a query that can search an Oracle clob for any record that contains an ampersand character where the word in which the character is located in is not one of any of the following (or possible any escape code):
& - &
< - <
> - >
" - "
' - &apos;
I want to extract 5 character before the ampersand and 5 characters after the ampersand so i can see the actual value.
Basically i want to search for any record that contains those fields and replace it with the escape code.
At the moment i am doing something like this:
Select * from articles
where dbms_lob.instr(article_summary , '&amp' ) = 0 and dbms_lob.instr(article_summary , '&' )
Update
If i was to use a regular expression, how would i specify it if i want to retrieve all fields where the value is & followed by any character other than 'a'?
You can use DBMS_XMLGEN.CONVERT for this. The second parameter is optional and if left out will escape the the XML special characters.
select DBMS_XMLGEN.CONVERT(article_summary)
from articles;
But, if article summary contains a mixture of escaped and unescaped characters, then this will give wrong result. Easiest way to solve it, is to unescape the characters first and then escape it.
select DBMS_XMLGEN.CONVERT(
DBMS_XMLGEN.CONVERT(article_summary,1) --1 as parameter does unescaping
)
from articles;

Search special characters from SQL table

Text = “World“ world ” <world <Word> ‘ word’ ‘ word“ word’ =1254.25 = 2545.58. 20%
Hey guys,
I need to search a word from a string which was saved in my db. The searching word contains special characters such as ""'!##$%^<>. Below is the sql select query used for the search.
select * from TABLE where TABLE.text like ('%'+ '“ World' +'%')
as a result some of the special character are not searched. Characters such as double quotation, single quotation are not searched from this. need assistance with solving this problem asap. thank you :)
These Special characters are Unicode characters, When ever dealing with these characters in sql server you have to tell sql server explicitly that there can be some unicode characters in the strings you are about to manipulate by prefixing your strings with N'String'
In your case you would write a query something like ....
select * from TABLE
where TABLE.text like N'%'+ N'“ World' + N'%'
you can use the ESCAPE clause and escape your parameter value. http://technet.microsoft.com/en-us/library/ms179859.aspx
so for example to search for a string containing the character %
select * from TABLE where TABLE.text like ('%'+ N'\%' +'%') ESCAPE '\'