Read this SQL tutorial to learn when to use SELECT, JOIN, subselects and UNION to access multiple tables with a single statement.

I need to search about twenty columns for given a string with wildcards. The query essentially looks like this: SELECT * FROM `the_table` WHERE `field1` LIKE 'string%' OR `field2` LIKE 'string ...

So, you want to iterate through millions of table rows coming as a result of some MySQL select query because you want to do your thingie with them, but alas!, your lovely database admin doesn't like ...

In this syntax: First, specify one or more columns from which you want to select data after the SELECT keyword. If the select_list has multiple columns, you need to separate them by a comma (,).