Difference between LIKE and = in MYSQL?

Question

What\'s the difference between

SELECT foo FROM bar WHERE foobar=\'$foo\'

AND

SELECT foo FROM bar WHERE foobar LIKE\'$foo\'         


        

Answer 1

I found an important difference between LIKE and equal sign = !

Example: I have a table with a field "ID" (type: int(20) ) and a record that contains the value "123456789"

If I do:

SELECT ID FROM example WHERE ID = '123456789-100'

Record with ID = '123456789' is found (is an incorrect result)

If I do:

SELECT ID FROM example WHERE ID LIKE '123456789-100'

No record is found (this is correct)

So, at least for INTEGER-fields it seems an important difference...

Answer 2

With the example in your question there is no difference.

But, like Jesse said you can do wildcard matching

SELECT foo FROM bar WHERE foobar LIKE "Foo%"

SELECT foo FROM bar WHERE foobar NOT LIKE "%Foo%"

More info:

http://dev.mysql.com/doc/refman/5.0/en/string-comparison-functions.html

Answer 3

In my case I find Like being faster than =

• Like fetched a number of rows in 0.203 secs the first time then 0.140 secs

• = returns fetched the same rows in 0.156 secs constantly

Take your choice

Answer 4

The end result will be the same, but the query engine uses different logic to get to the answer. Generally, LIKE queries burn more cycles than "=" queries. But when no wildcard character is supplied, I'm not certain how the optimizer may treat that.

Answer 5

LIKE can do wildcard matching:

SELECT foo FROM bar WHERE foobar LIKE "Foo%"

If you don't need pattern matching, then use = instead of LIKE. It's faster and more secure. (You are using parameterized queries, right?)

Answer 6

In your example, they are semantically equal and should return the same output.

However, LIKE will give you the ability of pattern matching with wildcards.

You should also note that = might give you a performance boost on some systems, so if you are for instance, searching for an exakt number, = would be the prefered method.