Обсуждение: Select into with dynamic criteria in a plpgsql function

I've got a function defined in PL/PgSQL to update some fields in a 
record where the criteria for pulling out some other values from a table 
is dynamic.

I define a string called account_criteria to which I assign a normal SQL 
WHERE clause based on some work done earlier in the function. I then 
need to pull out some values from a table based on that where clause so 
I'm doing something like:

SELECT amt_ytd INTO yesterday_amt_ytd FROM finbalance WHERE 
account_criteria;

Which returns the following:

ERROR: argument of WHERE must be type boolean, not type text
SQL state: 42804
Context: SQL statement "SELECT amt_ytd FROM finbalance WHERE  $1 "
PL/pgSQL function "fn_update_daily_balance" line 27 at SQL statement

I assume I would need something like EXECUTE to do this... but SELECT 
INTO is not supported in EXECUTE so I have a bit of a conundrum. :(

Can anyone offer some suggestion(s) on how can I make my function 
behave? Non-violent suggestions would be preferable.

-- 
Paul Lambert
Database Administrator
AutoLedgers

Paul Lambert wrote:
> I've got a function defined in PL/PgSQL to update some fields in a 
> record where the criteria for pulling out some other values from a table 
> is dynamic.
> 
> I define a string called account_criteria to which I assign a normal SQL 
> WHERE clause based on some work done earlier in the function. I then 
> need to pull out some values from a table based on that where clause so 
> I'm doing something like:
> 
> SELECT amt_ytd INTO yesterday_amt_ytd FROM finbalance WHERE 
> account_criteria;
> 
> Which returns the following:
> 
> ERROR: argument of WHERE must be type boolean, not type text
> SQL state: 42804
> Context: SQL statement "SELECT amt_ytd FROM finbalance WHERE  $1 "
> PL/pgSQL function "fn_update_daily_balance" line 27 at SQL statement
> 
> I assume I would need something like EXECUTE to do this... but SELECT 
> INTO is not supported in EXECUTE so I have a bit of a conundrum. :(
> 
> Can anyone offer some suggestion(s) on how can I make my function 
> behave? Non-violent suggestions would be preferable.
> 

Ignore this - I didn't notice execute <blah> into <variable> - I've just 
re-read the manual and worked it out.

Thanks.

-- 
Paul Lambert
Database Administrator
AutoLedgers