Re: ORDER BY COLUMN_A, (COLUMN_B or COLUMN_C), COLUMN_D

<div class="moz-cite-prefix">On 13/09/12 09:44, Rodrigo Rosenfeld Rosas wrote:<br /></div><blockquote
cite="mid:CAGmv+wKCpc9VeyYp6nS9WL1vrtX=3+i87mFVMP4sEpB1LyPGQA@mail.gmail.com"type="cite"><pre wrap="">This is my first
messagein this list :)
 

I need to be able to sort a query by column A, then B or C (which one
is smaller, both are of the same type and table but on different left
joins) and then by D.

How can I do that?

Thanks in advance,
Rodrigo.


</pre></blockquote><font face="Courier New, Courier, monospace">I created a script '</font><font face="Courier New,
Courier,monospace"><font face="Courier New,       Courier, monospace">variable_sort_order.sql</font>'...<br /><br />
DROPTABLE IF EXISTS tabc;<br /><br /> CREATE TABLE tabc<br /> (<br />     id  serial PRIMARY KEY,<br />     a   int,<br
/>    b   int,<br />     c   int,<br />     d   int<br /> );<br /><br /><br /> INSERT INTO tabc (a, b, c, d)<br />
VALUES(generate_series(1, 6), <br />         3 * random(), <br />         3 * random(), <br />        
generate_series(1,5));       <br /><br /><br /> SELECT <br />     *<br /> FROM<br />     tabc t<br /> ORDER BY<br />
   t.a,<br />     LEAST(t.b, t.c),<br />     t.d<br /> /**/;/**/<br /><br /> gavin=> \i variable_sort_order.sql<br
/>DROP TABLE<br /> psql:variable_sort_order.sql:10: NOTICE:  CREATE TABLE will create implicit sequence "tabc_id_seq"
forserial column "tabc.id"<br /> psql:variable_sort_order.sql:10: NOTICE:  CREATE TABLE / PRIMARY KEY will create
implicitindex "tabc_pkey" for table "tabc"<br /> CREATE TABLE<br /> INSERT 0 30<br />  id | a | b | c | d <br />
----+---+---+---+---<br/>  25 | 1 | 0 | 3 | 5<br />   7 | 1 | 1 | 1 | 2<br />   1 | 1 | 3 | 2 | 1<br />  13 | 1 | 2 | 3
|3<br />  19 | 1 | 2 | 2 | 4<br />   8 | 2 | 0 | 2 | 3<br />  14 | 2 | 0 | 2 | 4<br />  26 | 2 | 2 | 1 | 1<br />  20 |
2| 1 | 2 | 5<br />   2 | 2 | 2 | 2 | 2<br />   3 | 3 | 0 | 2 | 3<br />  21 | 3 | 1 | 1 | 1<br />  27 | 3 | 1 | 3 | 2<br
/> 15 | 3 | 3 | 1 | 5<br />   9 | 3 | 3 | 2 | 4<br />   4 | 4 | 0 | 1 | 4<br />  10 | 4 | 3 | 0 | 5<br />  16 | 4 | 1 |
3| 1<br />  22 | 4 | 1 | 1 | 2<br />  28 | 4 | 2 | 3 | 3<br />  11 | 5 | 0 | 1 | 1<br />  17 | 5 | 0 | 3 | 2<br />  23
|5 | 1 | 1 | 3<br />   5 | 5 | 3 | 1 | 5<br />  29 | 5 | 3 | 2 | 4<br />  18 | 6 | 2 | 0 | 3<br />  12 | 6 | 1 | 1 |
2<br/>  24 | 6 | 3 | 1 | 4<br />  30 | 6 | 1 | 3 | 5<br />   6 | 6 | 3 | 2 | 1<br /> (30 rows)<br /><br /><br /><br
/><br/></font><br />