SQL Server 2008 R2 Inner Join Fails to match varchar fields because it contains special characters

Question

We are using Microsoft SQL Server 2008 R2 for one of our Classic ASP applications.

We have two tables:

• TableA
• TableB

TableA has the following columns:

• InstName(varchar[1024])

TableB has these columns:

• InstitutionName(varchar[1024])

However, we came across some data like the following

TableA

InstName with value University of Nantes [ Universites de Nantes ]

TableB

InstitutionName with value University of Nantes [ Universites de Nantes ]

We need to run inner join select queries on the said 2 tables:

select *
from TableA
inner join TableB on TableA.InstName LIKE TableB.InstitutionName

Sadly, this inner join fails to match the columns with the value of University of Nantes [ Universites de Nantes ]

I do know that "[]" square brackets have special meaning in Microsoft SQL Server 2008 R2.

Please modify the said inner join select query in such a way that it escapes the "[]" square brackets so that the match is found, and paste the said modified query on this stackoverflow.com ticket.

Furthermore, please advise on how I should deal with other special characters like "[]" square brackets that have special meaning in Microsoft SQL Server 2008 R2.

Answer 1

Use = instead of LIKE .

Your query should read:

select *
     from TableA
     inner join TableB
     on TableA.InstName = TableB.InstitutionName

I confirmed with the following:

declare @t1 table(name varchar(1024))
insert into @t1(name) values('[ Universites de Nantes ]');

declare @t2 table(name varchar(1024))
insert into @t2(name) values('[ Universites de Nantes ]');

--nothing returned
    select * from @t1 t1
    inner join @t2 t2 ON t2.name LIKE t1.name

--one record returned
    select * from @t1 t1
    inner join @t2 t2 ON t2.name = t1.name

Answer 2

If you need to JOIN on two fields using LIKE that contain [ , you'll need to escape the opening bracket since the bracket is a wildcard character. For any wildcard characters, you can use brackets [] - this will search for any single character within the specified range.

For example, this should work in your scenario using REPLACE :

select * 
from yourtable t inner join 
    yourtable2 t2 on t.field like replace(t2.field,'[', '[[]')

• SQL Fiddle Demo

Alternatively, for your sample data, you have no reason to use LIKE as = would work the same.