$query = "SELECT * FROM table_name WHERE text_is_store LIKE '$lookingfor'";
thats pretty simple to me.. some might not think so.
Obviously its a bit more complicated.. because if you put $lookingfor='Today' then you will get every documents with the word 'Today' returned .. so you need to do some filtering and more important you need to consider the amount of datas which are going to be stored.
1 table with 5000 data is ok.. 1 table with 500 000 .. you might get a bit of lag on the Query.
Overall, if you have some basic knowledge of programming its dead easy.