Thread: When is Like different to =

All,

I've a query:

SELECT
    c.code, c.pc_no, jl.event_no, jl.order_number, jl.location, s.status,
cs.commercial_status
FROM
    ((codes as c JOIN job_list as jl ON c.id = jl.code_id) JOIN status as s
ON jl.event_no = s.event_no)
        JOIN commercial_status AS cs on jl.event_no = cs.event_no
WHERE
    (status = 'Job Allocated') AND (code_id = 39);

Where codes and job_list are tables and status is a view:

CREATE VIEW status AS
 SELECT job_list.event_no, status(job_list.event_no) AS status
   FROM job_list
   JOIN user_codes ON job_list.code_id = user_codes.code_id
  WHERE user_codes.user_name::name = "current_user"();

CREATE FUNCTION status(int4)
  RETURNS text AS
$BODY$SELECT
 CASE
            WHEN job_cancelled IS NOT NULL THEN 'Cancelled'::text
            WHEN job_sheet_received IS NOT NULL THEN 'Job Sheet
Received'::text
            WHEN works_complete IS NOT NULL THEN 'Works Complete'::text
            WHEN awaiting_action_id IS NOT NULL THEN 'Awaiting Action'::text
            WHEN attend_date IS NOT NULL THEN 'Job Attended'::text
            WHEN issued_to IS NOT NULL THEN 'Job Allocated'::text
            ELSE 'Not Allocated'::text
 END
FROM
 job_list
WHERE
 event_no = $1$BODY$
  LANGUAGE 'sql' STABLE;

The above query should return one row from my current database but does not.
If I change the where clause from (status = 'Job Allocated') AND (code_id =
39)
to
(status LIKE 'Job Allocated') AND (code_id = 39)
it does return the row.

What am I missing?

Regards,

Ben

After some more digging I found there was an index:

CREATE INDEX job_list_status_idx
  ON job_list
  USING btree
  (status(event_no));

I had previously created.  I must have changed the function from IMMUTABLE
to STABLE after creating the index or I assume I wouldn't have been able to
create the index.  When I dropped the index Like and = started working
correctly.

BTW should there be check so an error is thrown if I try to change a
function used in an index from IMMUTABLE to STABLE?

Ben

"Ben Trewern" <ben.trewern@_nospam_mowlem.com> wrote in message
news:dbr6fj$10p3$1@news.hub.org...
> All,
>
> I've a query:
>
> SELECT
>    c.code, c.pc_no, jl.event_no, jl.order_number, jl.location, s.status,
> cs.commercial_status
> FROM
>    ((codes as c JOIN job_list as jl ON c.id = jl.code_id) JOIN status as s
> ON jl.event_no = s.event_no)
>        JOIN commercial_status AS cs on jl.event_no = cs.event_no
> WHERE
>    (status = 'Job Allocated') AND (code_id = 39);
>
> Where codes and job_list are tables and status is a view:
>
> CREATE VIEW status AS
> SELECT job_list.event_no, status(job_list.event_no) AS status
>   FROM job_list
>   JOIN user_codes ON job_list.code_id = user_codes.code_id
>  WHERE user_codes.user_name::name = "current_user"();
>
> CREATE FUNCTION status(int4)
>  RETURNS text AS
> $BODY$SELECT
> CASE
>            WHEN job_cancelled IS NOT NULL THEN 'Cancelled'::text
>            WHEN job_sheet_received IS NOT NULL THEN 'Job Sheet
> Received'::text
>            WHEN works_complete IS NOT NULL THEN 'Works Complete'::text
>            WHEN awaiting_action_id IS NOT NULL THEN 'Awaiting
> Action'::text
>            WHEN attend_date IS NOT NULL THEN 'Job Attended'::text
>            WHEN issued_to IS NOT NULL THEN 'Job Allocated'::text
>            ELSE 'Not Allocated'::text
> END
> FROM
> job_list
> WHERE
> event_no = $1$BODY$
>  LANGUAGE 'sql' STABLE;
>
> The above query should return one row from my current database but does
> not. If I change the where clause from (status = 'Job Allocated') AND
> (code_id = 39)
> to
> (status LIKE 'Job Allocated') AND (code_id = 39)
> it does return the row.
>
> What am I missing?
>
> Regards,
>
> Ben
>