SELECT COUNT(DISTINCT seq) FROM Peptide;
####
EXPLAIN AND DESCRIBE:
mysql> explain select count(distinct seq) from Peptide;
+---------+------+---------------+------+---------+------+---------+-------+
| table | type | possible_keys | key | key_len | ref | rows | Extra |
+---------+------+---------------+------+---------+------+---------+-------+
| Peptide | ALL | NULL | NULL | NULL | NULL | 1860342 | |
+---------+------+---------------+------+---------+------+---------+-------+
1 row in set (0.02 sec)
mysql> desc Peptide;
+--------+---------------------------+------+-----+------------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------+---------------------------+------+-----+------------+----------------+
| pepid | int(10) unsigned zerofill | | PRI | NULL | auto_increment |
| proid | int(10) unsigned zerofill | | MUL | 0000000000 | |
| seq | tinytext | | MUL | | |
| mh | double | | | 0 | |
| expect | double | | | 0 | |
| start | int(11) | | | 0 | |
| end | int(11) | | | 0 | |
| charge | tinyint(1) unsigned | YES | | NULL | |
| delta | float | | | 0 | |
| dida | int(11) | | | 0 | |
| didb | int(11) | | | 0 | |
| didc | int(11) | | | 0 | |
+--------+---------------------------+------+-----+------------+----------------+
12 rows in set (0.00 sec)
####
C:\testing\scripts>perl stat_tester.pl
Connected
DBD::mysql::db do failed: Lost connection to MySQL server during query at stat_tester.pl line 54.