Produce a time-of-day summary for records : DateTime « Data Type « SQL / MySQL

1. SQL / MySQL
2. Data Type
3. DateTime

Produce a time-of-day summary for records

     
mysql>
mysql> CREATE TABLE mail
    -> (
    ->  t               DATETIME,       # when message was sent
    ->  senderUser      CHAR(8),        # sender (source user and host)
    ->  senderHost      CHAR(20),
    ->  recipientUser   CHAR(8),        # recipient (destination user and host)
    ->  recipientHost   CHAR(20),
    ->  size    BIGINT,         # message size in bytes
    ->  INDEX   (t)
    -> );
Query OK, 0 rows affected (0.01 sec)

mysql>
mysql> INSERT INTO mail (t,senderHost,senderUser,recipientHost,recipientUser,size)
    ->  VALUES
    ->          ('2010-05-11 10:15:08','saturn','barb','mars','tricia',58274),
    ->          ('2010-05-12 12:48:13','mars','tricia','venus','gene',194925),
    ->          ('2010-05-12 15:02:49','mars','phil','saturn','phil',1048),
    ->          ('2010-05-13 13:59:18','saturn','barb','venus','tricia',271),
    ->          ('2010-05-14 09:31:37','venus','gene','mars','barb',2291),
    ->          ('2010-05-14 11:52:17','mars','phil','saturn','tricia',5781),
    ->          ('2010-05-14 14:42:21','venus','barb','venus','barb',98151),
    ->          ('2010-05-14 17:03:01','saturn','tricia','venus','phil',2394482),
    ->          ('2010-05-15 07:17:48','mars','gene','saturn','gene',3824),
    ->          ('2010-05-15 08:50:57','venus','phil','venus','phil',978),
    ->          ('2010-05-15 10:25:52','mars','gene','saturn','tricia',998532),
    ->          ('2010-05-15 17:35:31','saturn','gene','mars','gene',3856),
    ->          ('2010-05-16 09:00:28','venus','gene','mars','barb',613),
    ->          ('2010-05-16 23:04:19','venus','phil','venus','barb',10294),
    ->          ('2010-05-17 12:49:23','mars','phil','saturn','tricia',873),
    ->          ('2010-05-19 22:21:51','saturn','gene','venus','gene',23992)
    -> ;
Query OK, 16 rows affected (0.00 sec)
Records: 16  Duplicates: 0  Warnings: 0

mysql>
mysql>
mysql> SELECT HOUR(t) AS hour,
    -> COUNT(*) AS 'number of messages',
    -> SUM(size) AS 'number of bytes sent'
    -> FROM mail
    -> GROUP BY hour;
+------+--------------------+----------------------+
| hour | number of messages | number of bytes sent |
+------+--------------------+----------------------+
|    7 |                  1 |                 3824 |
|    8 |                  1 |                  978 |
|    9 |                  2 |                 2904 |
|   10 |                  2 |              1056806 |
|   11 |                  1 |                 5781 |
|   12 |                  2 |               195798 |
|   13 |                  1 |                  271 |
|   14 |                  1 |                98151 |
|   15 |                  1 |                 1048 |
|   17 |                  2 |              2398338 |
|   22 |                  1 |                23992 |
|   23 |                  1 |                10294 |
+------+--------------------+----------------------+
12 rows in set (0.00 sec)

mysql>
mysql> drop table mail;
Query OK, 0 rows affected (0.00 sec)

   
    
    
    
    
  

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