where clause - mysql select: randomly select with another criteria if not met the max. number of rows -

where clause - mysql select: randomly select with another criteria if not met the max. number of rows -

i need select table under criteria limit of 20 randomly. used next same

select *, rand() table column1 '%text%' order rand() limit 20

but criteria wont meet , less 20 rows selected . in such cases needed add together select statement in there criteria , not equal previous selection (i mean distinct) how can accomplish single query (something conditional query).

mytable defines

create table if not exists `mytable`( `id` int(11) not null auto_increment, `name` varchar(100) not null, `house` varchar(100) not null, `place` varchar(100) not null, primary key (`vinrav_examz_id`) );

content of table

id------name-------house------place-- 1-------data1------data2------data3-- 2-------data4------data5------data6-- 3-------data7------data8------data6-- 4-------data9------data9------data10-- 5-------data11-----data8------data12--

then first query

select *, rand() mytable palce 'data6' order rand() limit 20

which give 2 rows < 20.

2-------data4------data5------data6-- 3-------data7------data8------data6--

in case execute

select *, rand() mytable house 'data8' order rand() limit 20

which return

3-------data7------data8------data6-- 5-------data11-----data8------data12--

then combined need get

2-------data4------data5------data6-- 3-------data7------data8------data6-- 5-------data11-----data8------data12--

thankz in advance

select * table -- column1 '%text%' -- (notice removed where) order case when column1 '%text%' 1 when column1 '%secondcriteria%' 2 when column1 '%thirdcriteria%' 3 else 4 end, rand() limit 20

select where-clause