Sql database doesn't use index in like statement if it starts with % .. like 'abcd%' would work though...
To use an index you can store your value using reverse function and index it .. then your like would use the index. 2014-02-11 20:23 GMT-05:00 Zhigang Zhang <zzgang2...@gmail.com>: > For example: > > > > Select * from T where col like '%abcd'; > > > > The table T is myisam table and we created a index on col. > > > > As we known, this like sql does not use the index created on col, it > confuse > me, why? > > > > I think in mysiam engine, the index data is smaller, it can use index link > list to optimize it so as to reduce the disk scan than to the whole table > scan. > > > > Thanks. > > > > Zhigang > >
