Mega Code Archive
Count and group
<![CDATA[
/*
mysql> /* find out how many Birds each owner has: */
mysql> SELECT owner, COUNT(*) FROM Bird GROUP BY owner;
+-------+----------+
| owner | COUNT(*) |
+-------+----------+
| Joe | 1 |
| Yin | 2 |
+-------+----------+
2 rows in set (0.01 sec)
*/
Drop table Bird;
CREATE TABLE Bird (
name VARCHAR(20),
owner VARCHAR(20),
species VARCHAR(20),
sex CHAR(1),
birth DATE,
death DATE
);
INSERT INTO Bird VALUES ('BlueBird','Joe','Car','f','1999-03-30',NULL);
INSERT INTO Bird VALUES ('RedBird','Yin','Bus','m','1979-04-30',1998-01-30);
INSERT INTO Bird VALUES ('RedBird','Yin','Bus','m','1998-01-30',NULL);
/* find out how many Birds each owner has: */
SELECT owner, COUNT(*) FROM Bird GROUP BY owner;
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