Hi there:
I have a "How do I..." SQL question regarding selecting
distinct values from a field not included in an aggregated
query when LIMIT is in effect, illustrated by the
following example:
Table a contains the names of individuals, the places
they have visited and the year in which they were visited.
Let's see who has visited where and when:
SELECT * FROM a;
name place year
------ ------- ------kim north 2004kim south 2003kim south 2003bob west 2004bob west 2004bob
west 2003joe south 2004joe south 2005sue west 2004bob east 2003joe east 2004joe
east 2004sue south 2004bob north 2004bob north 2005
Summarize data by number of places visited by year:
SELECT count(*) AS count, name, year FROM a GROUP BY name, year ORDER BY count DESC, name ASC;
count name year
------- ------ ------ 3 bob 2004 3 joe 2004 2 bob 2003 2 kim 2003 2 sue 2004 1
bob 2005 1 kim 2004 1 joe 2005
Return only four rows beginning at second row:
SELECT count(*) AS count, name, year FROM a GROUP BY name, year ORDER BY count DESC, name ASC LIMIT 4 OFFSET 1;
count name year
------- ------ ------ 3 joe 2004 s,e,e 2 bob 2003 w,e 2 kim 2003 s,s 2 sue 2004 s,w
Select only places visited included in LIMITed query:
SELECT DISTINCT place FROM a ????;
place
-------southwesteast
Note that the place north does not appear in the last result
because north was only visited by bob in 2005 and kim in 2004,
records which are not included in the limited result.
Any help appreciated.
-Bob