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How can I pick this with sql?

Posted on 2015-02-17
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Last Modified: 2015-02-18
hi,

I have table where in one field the data is like

{name,100}
{name,101}
{name,102}
{secondname,200} {name,100}
{name,103}
{name,104}

so my goal is to pick 100 from here but when I use like bellow:

100
101
102
103
104

how can I do this with sql... i'm using postgress v8
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Question by:hi4ppl
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5 Comments
 
LVL 14

Expert Comment

by:Mark Bullock
ID: 40615936
Here's a way to get the result you want. You can play with this at SQL Fiddle http://sqlfiddle.com/#!11/8c057/5

CREATE TABLE mytable 
	(
     json varchar(30)
    );

INSERT INTO mytable
(json)
VALUES
('{name,100}'),
('{name,101}'),
('{name,102}'),
('{secondname,200} {name,100}'),
('{name,103}'),
('{name,104}');

select substring(json from 7 for 3)
from mytable
where json like '{name%';

Open in new window

0
 
LVL 1

Author Comment

by:hi4ppl
ID: 40615946
sorry I did mistake in providing the sample data well... here is the corrected one...

{name,10}
{name,101}
{name,10002}
{secondname,200} {name,1003}
{name,104}
{name,1005}

as the length of placement is not fixed ...plus thee placement of name sometimes moves....so the result that i'm looking for is :

 10
101
1002
1003
104
1005

thanks
0
 
LVL 49

Accepted Solution

by:
PortletPaul earned 2000 total points
ID: 40615966
this would be far simpler in version 9.x

A way:
select
       replace(substring(thatpart,commapos+1), '}','') as picked
     , thatfield
from (
      select
             thatfield
           , split_part(thatfield, '} {', c+1) thatpart
           , strpos(split_part(thatfield, '} {', c+1), ',') commapos
      from (
            select
                    thatfield
                  , ((length(thatfield) - length(replace(thatfield,'} {',''))) / 3) as c
            from Table1
          ) x
     ) y
;

Open in new window


Or, without the nesting:
select
  replace(substring(split_part(thatfield, '} {', ((length(thatfield) - length(replace(thatfield,'} {',''))) / 3)+1),strpos(split_part(thatfield, '} {', ((length(thatfield) - length(replace(thatfield,'} {',''))) / 3)+1), ',')+1), '}','') as picked
, thatfield
from table1
;

Open in new window


Results:
| PICKED |                    THATFIELD |
|--------|------------------------------|
|     10 |                    {name,10} |
|    101 |                   {name,101} |
|  10002 |                 {name,10002} |
|   1003 | {secondname,200} {name,1003} |
|    104 |                   {name,104} |
|   1005 |                  {name,1005} |

Open in new window


see it at: http://sqlfiddle.com/#!11/90cff/2
0
 
LVL 1

Author Comment

by:hi4ppl
ID: 40615970
Hi,

thank you very much it looks good... but is there a way I can simplify this as I want to sometimes sum(thatfield) ...

regards
0
 
LVL 49

Expert Comment

by:PortletPaul
ID: 40615979
Good luck with that simplification (note: if I could have I would have).

I don't use PostgreSQL every day, so there might be better ways I don't know about, and the job would be really simple if REVERSE() existed in 8.x (it's available in 9.x)

Plus you would have to add the necessary conversion to a number to perform a SUM(), and on top of that ensure you are only dealing with strings that can be converted to numbers.

Thus: I don't think so, but I could be wrong.
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