create table t1 (a date not null, b varchar(50) not null, c varchar(50) not null, d enum('m', 'w'), primary key(a,b,c,d)) engine='MyISAM' 
partition by key (a,b,c,d) (
partition pa1 DATA DIRECTORY =
'/tmp' INDEX DIRECTORY =
'/tmp' max_rows=20 min_rows=2,
partition pa2 DATA DIRECTORY =
'/tmp' INDEX DIRECTORY =
'/tmp' max_rows=30 min_rows=3,
partition pa3 DATA DIRECTORY =
'/tmp' INDEX DIRECTORY =
'/tmp' max_rows=30 min_rows=4,
partition pa4 DATA DIRECTORY =
'/tmp' INDEX DIRECTORY =
'/tmp' max_rows=40 min_rows=2);
show create table t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` date NOT NULL,
  `b` varchar(50) NOT NULL,
  `c` varchar(50) NOT NULL,
  `d` enum('m','w') NOT NULL DEFAULT 'm',
  PRIMARY KEY (`a`,`b`,`c`,`d`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 DATA DIRECTORY='/tmp/' INDEX DIRECTORY='/tmp/' /*!50100 PARTITION BY KEY (a,b,c,d) (PARTITION pa1 MAX_ROWS = 20 MIN_ROWS = 2 DATA DIRECTORY = '/tmp' INDEX DIRECTORY = '/tmp' ENGINE = MyISAM, PARTITION pa2 MAX_ROWS = 30 MIN_ROWS = 3 DATA DIRECTORY = '/tmp' INDEX DIRECTORY = '/tmp' ENGINE = MyISAM, PARTITION pa3 MAX_ROWS = 30 MIN_ROWS = 4 DATA DIRECTORY = '/tmp' INDEX DIRECTORY = '/tmp' ENGINE = MyISAM, PARTITION pa4 MAX_ROWS = 40 MIN_ROWS = 2 DATA DIRECTORY = '/tmp' INDEX DIRECTORY = '/tmp' ENGINE = MyISAM) */
insert into t1 values 
('1975-01-01', 'abcde', 'abcde','m'), 
('1983-12-31', 'cdef', 'srtbvsr', 'w'), 
('1980-10-14', 'fgbbd', 'dtzndtz', 'w'),
('2000-06-15', 'jukg','zikhuk','m');
select * from t1;
a	b	c	d
1975-01-01	abcde	abcde	m
1980-10-14	fgbbd	dtzndtz	w
1983-12-31	cdef	srtbvsr	w
2000-06-15	jukg	zikhuk	m
select * from t1 where a<19851231;
a	b	c	d
1975-01-01	abcde	abcde	m
1980-10-14	fgbbd	dtzndtz	w
1983-12-31	cdef	srtbvsr	w
drop table t1;