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From:Paul Nowosielski Date:June 23 2006 7:27pm
Subject:Left Join Help
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Dear All,

I've been hashing out this query for awhile with no luck as of yet.
Basically the query works if I put a limit of 500 or so but when I do the full 
query it takes up so many resource that the database engine is useless.

Here is the query:

SELECT DISTINCT (td.td_id)  ,td.venue_id as ven_id, td.td_date as td_date, 
art.NAME as art_name,art.WEB as art_url, artd.artist_id as art_id, tv.ID, 
tv.NAME as ven_name, tv.ADDR1 ven_add0, tv.ADDR2 as ven_add1,tv.CITY 
ven_city,tv.STATE ven_state, tv.ZIPCODE ven_zip,tv.COUNTRY ,tv.WEBSITE as 
ven_url,tvc.SIZE as capacity,
tvage.TYPE as age,tv.TICKETAGNCY1 as tix0, tv.TICKETAGNCY2 as tix1

FROM tourdates td, tbl_ARTST as art, artist_tourdate artd , tbl_VENUES tv, 
tbl_VENUE_CAPACITY tvc 
,tbl_VENUE_AGE_XREF tvax, tbl_VENUE_AGES tvage

LEFT JOIN tbl_VENUE_CAPACITY ON (tv.ID=tvc.VENUE_ID)

LEFT JOIN tbl_VENUE_AGE_XREF ON (tv.ID=tvax.VENUE_ID)

LEFT JOIN tbl_VENUE_AGES ON (tvax.VENUE_ID = tvage.PKEY)


WHERE 

td_date > NOW() AND (td.td_id = artd.td_id AND artd.artist_id = art.PKEY AND 
td.venue_id=tv.ID) LIMIT 500

Here is a description of the query:
+--------------------+--------+-----------------------+---------+---------+----------------+-------+------------------------------+
| table              | type   | possible_keys         | key     | key_len | 
ref            | rows  | Extra                        |
+--------------------+--------+-----------------------+---------+---------+----------------+-------+------------------------------+
| td                 | range  | PRIMARY,idx01,dateidx | dateidx |       4 | 
NULL           | 43943 | Using where; Using temporary |
| artd               | ref    | idx01,idx02           | idx01   |       4 | 
td.td_id       |     1 |                              |
| art                | eq_ref | PRIMARY,idx02         | PRIMARY |       4 | 
artd.artist_id |     1 | Using where                  |
| tv                 | eq_ref | PRIMARY,idx04         | PRIMARY |       4 | 
td.venue_id    |     1 | Using where                  |
| tvage              | ALL    | NULL                  | NULL    |    NULL | 
NULL           |     4 |                              |
| tvc                | ALL    | NULL                  | NULL    |    NULL | 
NULL           | 10261 |                              |
| tbl_VENUE_CAPACITY | index  | NULL                  | idx01   |       5 | 
NULL           | 10261 | Using index; Distinct        |
| tvax               | index  | NULL                  | idx01   |       8 | 
NULL           | 11616 | Using index; Distinct        |
| tbl_VENUE_AGE_XREF | index  | NULL                  | idx01   |       8 | 
NULL           | 11616 | Using index; Distinct        |
| tbl_VENUE_AGES     | index  | NULL                  | PRIMARY |       4 | 
NULL           |     4 | Using index; Distinct        |
+--------------------+--------+-----------------------+---------+---------+----------------+-------+------------------------

I need to be able to run the full query on a daily basis without killing the 
DB engine. 

The query needs to pull in about 50,000 results.

Does anyone see a way to optimize this query or rewrite it so it doesn't cause 
a huge system load?

Thank you,

-- 
Paul Nowosielski
Webmaster


Thread
Left Join HelpPaul Nowosielski23 Jun
  • Re: Left Join HelpGerald L. Clark23 Jun
  • Re: Left Join HelpBrent Baisley23 Jun
  • Re: Left Join HelpGerald L. Clark23 Jun
    • Re: Left Join Help SOLVEDPaul Nowosielski23 Jun
  • Re: Left Join HelpPeter Brawley23 Jun
    • Re: Left Join HelpDaniel McQuay24 Jun