7 messages in com.mysql.lists.mysqlRe: strange order by problem| From | Sent On | Attachments |
|---|---|---|
| Claire Lee | 27 Sep 2005 12:47 | |
| Gordon Bruce | 27 Sep 2005 13:12 | |
| SGr...@unimin.com | 27 Sep 2005 13:13 | |
| Hassan Schroeder | 27 Sep 2005 13:43 | |
| 2wsxdr5 | 27 Sep 2005 13:43 | |
| Claire Lee | 27 Sep 2005 14:08 | |
| Hassan Schroeder | 27 Sep 2005 14:27 |
| Subject: | Re: strange order by problem |
|---|---|
| From: | 2wsxdr5 (2wsx...@cox.net) |
| Date: | 09/27/2005 01:43:30 PM |
| List: | com.mysql.lists.mysql |
SGr...@unimin.com wrote:
Claire Lee <jing...@yahoo.com> wrote on 09/27/2005 03:48:11 PM:
I need to order a few names by the number following the main name. For example swap2, swap3, swap10 in the order of swap2, swap3, swap10, not in swap10, swap2, swap3 as it will happen when I do an order by.
So I came up with the following query:
mysql> select distinct secname, date from optresult where secname like 'swap%' and date like '2005-09-2%' order by if (secname like 'swap%',(right(secname,lengt h(secname)-locate('p',secname))+0), secname);
I was hoping it will order by the number following each 'swap' in the secname, it doesn't work. It was ordered instead by secname.
+----------+------------+ | secname | date | +----------+------------+ | SWAP0.25 | 2005-09-21 | | SWAP0.5 | 2005-09-21 | | SWAP1 | 2005-09-21 | | SWAP10 | 2005-09-26 | | SWAP10 | 2005-09-23 | | SWAP10 | 2005-09-21 | | SWAP2 | 2005-09-26 | | SWAP2 | 2005-09-23 | | SWAP2 | 2005-09-22 | | SWAP2 | 2005-09-21 | | SWAP3 | 2005-09-21 | | SWAP3 | 2005-09-26 | | SWAP3 | 2005-09-23 | | SWAP3 | 2005-09-22 | | SWAP5 | 2005-09-21 | | SWAP5 | 2005-09-26 | | SWAP5 | 2005-09-23 | | SWAP5 | 2005-09-22 | +----------+------------+
However, if I replace the second expression in the if statement by date, like the following, it's ordered by date as I would expect.
mysql> select distinct secname, date from optresult where secname like 'swap%' and date like '2005-09-2%' order by if (secname like 'swap%',date, secname); +----------+------------+ | secname | date | +----------+------------+ | SWAP3 | 2005-09-21 | | SWAP0.5 | 2005-09-21 | | SWAP5 | 2005-09-21 | | SWAP1 | 2005-09-21 | | SWAP10 | 2005-09-21 | | SWAP2 | 2005-09-21 | | SWAP0.25 | 2005-09-21 | | SWAP2 | 2005-09-22 | | SWAP3 | 2005-09-22 | | SWAP5 | 2005-09-22 | | SWAP10 | 2005-09-23 | | SWAP2 | 2005-09-23 | | SWAP3 | 2005-09-23 | | SWAP5 | 2005-09-23 | | SWAP10 | 2005-09-26 | | SWAP2 | 2005-09-26 | | SWAP3 | 2005-09-26 | | SWAP5 | 2005-09-26 | +----------+------------+
So I tried different combinations of the second and third expressions in the if statement in the query, the next one is the only one I can get it to order my way, which is not what I wanted of course since I don't want other secnames than swap% to order this way.
mysql> select distinct secname, date from optresult where secname like 'swap%' and date like '2005-09-2%' order by if (secname like 'swap%',(right(secname, leng th(secname)-locate('p', secname))+0), right(secname,length(secname)-locate('p',secname))+0); +----------+------------+ | secname | date | +----------+------------+ | SWAP0.25 | 2005-09-21 | | SWAP0.5 | 2005-09-21 | | SWAP1 | 2005-09-21 | | SWAP2 | 2005-09-22 | | SWAP2 | 2005-09-26 | | SWAP2 | 2005-09-21 | | SWAP2 | 2005-09-23 | | SWAP3 | 2005-09-22 | | SWAP3 | 2005-09-26 | | SWAP3 | 2005-09-21 | | SWAP3 | 2005-09-23 | | SWAP5 | 2005-09-23 | | SWAP5 | 2005-09-22 | | SWAP5 | 2005-09-26 | | SWAP5 | 2005-09-21 | | SWAP10 | 2005-09-26 | | SWAP10 | 2005-09-21 | | SWAP10 | 2005-09-23 | +----------+------------+
Can anyone see what problems I have in my query? I'm really stuck here. Thanks.
Claire
So you want to sort by secname except when secname starts with 'SWAP'
ORDER BY secname , if (secname like 'swap%' ,(right(secname, length(secname)-locate('p', secname))+0) ,0) , date;
by giving every *other* entry a default second sort-by of 0, they end up all sorting according to secname then date. It's when secname starts with swap that you get the sub-sorting value according to the end of the string. Make sense?
If secname is like 'swap%', why are you then using locate to find the p when it has to be the 4th letter or secname wouldn't be like 'swap%'. Also if your first order by argument is secname how is the second argument going to do anything since swap10 and swap2 are different the first argument is all you need to uniquely identify them.
-- Chris W
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