This was originally posted in French here.
There’s no string function in MySQL (and many other databases!) to help you find the number of occurrences of a string within another string. For example, how many times does « abc » appear in « abcbcbabcbacbcabcababcabacb » ?
I was asked this question on IRC a long time ago. Some poor soul was trying to find a particular subsequence in a genomic string (for instance « TAT ») in the following sequence :
Obviously, you can use your favorite programming language and do this kind of search programmatically but is there a way to do it in SQL?
Luckily, the answer is yes! The solution is simple and looks like …[Lire plus]