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

Please bear in mind as well that MySQL will do castings dependent upon the situation: LIKE will perform string cast, whereas = will perform int cast. Considering the situation of:

    (int)   (vchar2)
id  field1  field2
1   1       1
2   1       1,2

SELECT * FROM test AS a LEFT JOIN test AS b ON a.field1 LIKE b.field2

will produce

id  field1  field2  id  field1  field2
1   1       1       1   1       1
2   1       1,2     1   1       1

whereas

SELECT * FROM test AS a LEFT JOIN test AS b ON a.field1 = b.field2

will produce

id  field1  field2  id  field1  field2
1   1       1       1   1       1
1   1       1       2   1       1,2
2   1       1,2     1   1       1
2   1       1,2     2   1       1,2