If you don't want to see entire rows from your table, just name the columns
in which you're interested, separated by commas. For example, if you want to
know when your animals were born, select the name
and birth
columns:
mysql> SELECT name, birth FROM pet; +----------+------------+ | name | birth | +----------+------------+ | Fluffy | 1993-02-04 | | Claws | 1994-03-17 | | Buffy | 1989-05-13 | | Fang | 1990-08-27 | | Bowser | 1989-08-31 | | Chirpy | 1998-09-11 | | Whistler | 1997-12-09 | | Slim | 1996-04-29 | | Puffball | 1999-03-30 | +----------+------------+
To find out who owns pets, use this query:
mysql> SELECT owner FROM pet; +--------+ | owner | +--------+ | Harold | | Gwen | | Harold | | Benny | | Diane | | Gwen | | Gwen | | Benny | | Diane | +--------+
However, notice that the query simply retrieves the owner
field from
each record, and some of them appear more than once. To minimise the output,
retrieve each unique output record just once by adding the keyword
DISTINCT
:
mysql> SELECT DISTINCT owner FROM pet; +--------+ | owner | +--------+ | Benny | | Diane | | Gwen | | Harold | +--------+
You can use a WHERE
clause to combine row selection with column
selection. For example, to get birth dates for dogs and cats only,
use this query:
mysql> SELECT name, species, birth FROM pet -> WHERE species = "dog" OR species = "cat"; +--------+---------+------------+ | name | species | birth | +--------+---------+------------+ | Fluffy | cat | 1993-02-04 | | Claws | cat | 1994-03-17 | | Buffy | dog | 1989-05-13 | | Fang | dog | 1990-08-27 | | Bowser | dog | 1989-08-31 | +--------+---------+------------+
Posted by Myron Leathem on Friday May 2 2003, @6:27pm | [Delete] [Edit] |
From Myron
Note: if you leave out the comma after name below
the name selection will be ignored entirely.
mysql> SELECT name, birth FROM pet;
that is,
mysql> SELECT name birth FROM pet;
will generate the same results as
mysql> SELECT birth FROM pet;
Posted by [name withheld] on Friday June 6 2003, @5:39am | [Delete] [Edit] |
Not entirely true Myron,
if you do
mysql> SELECT name birth FROM pet;
it is the name column that gets selected, but in
the output it gets titled "birth" which might mislead
you to think that it was the birth column that was selected.
the SQL syntax allows you to rename the title of a
selected column with this syntax.
Cheers
/Henrik