LIKE operator

[StephenLeach]

In a SELECT statement I have a condition along the lines of columnName LIKE '%'.

I have noticed that this gives different results to '%' LIKE columnName.

Why is this? I would have thought that the LIKE operator would behave as the = operator, as in a=b is equivalent to saying b=a.

Does anyone know where I can can more information on this subject?

Thanks in advance

Stephen

 

[StephenLeach]

Just relised the answer myself...

a LIKE b is looking for pattern b inside string a

where as

b LIKE a is looking for pattern a inside string b


Sorry for opsting a question and then answering it five minutes later...

Stephen

 

[SQLSister]

Just so you know, using like % makes your query run without the use of indexes which will slow it down. Try not to use a wildcard as the first character for a search unless it is absolutely necessary.

 

[nickpark]

True but like

"H%"

will be fast as it will do a ranged scan