Count and group : Count « Select Clause « SQL / MySQL






  1. SQL / MySQL
  2. Select Clause
  3. Count

Count and group

/*

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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8.Get GROUP BY for COUNT
9.Use COUNT with condition
10.Simple COUNT
11.Performing Row and Column Counting
12.Use COUNT and GROUP
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