Quick search not returning all results

I hope someone can help me.

I have a grid application with the quick search box at the top. I have removed case sensitive under SQL. The quick search is setup to search 4 different fields in my database (Name, Surname, email, Identification number). The SC application connects to a MySQL database.

I have a a problem though. When searching for a record not all of them are found. For example if I search for some names they appear in the search results but if I search for other names (That I know is in the database) I get the “No results found” message.

What could be the cause of this?