Daily Archives: July 26, 2013

Some notes on MySQL index query

Some rules we should remember when doing MySQL index query: Index uses B-TREE, so be sure we understand how B-Tree works. Index is left-most, so if there is (c1, c2, c3) index, then query WHERE c1 = 1 AND c2 = 2 does use index, but not WHERE c2 = 2 When […]