Re: Anomaly with SUM().

are these float values?

Anthony Best wrote:

> I've noticed that the SUM() seems to overflow under some situations.
>
> The only difference is the order that the data is retrived from the
> database.
>
>
>
> accounting=# select  sum(amount)  from transactions, chart WHERE
> account=chart.id;
>         sum
> ---------------------
> 5.6843418860808e-14
> (1 row)
>
> accounting=# select  sum(amount)  from transactions, chart WHERE
> account=chart.id AND amount=amount;
> sum
> -----
>   0
> (1 row)
>
>
>
>
> More Info:
> accounting=# select  amount  from transactions, chart WHERE
> account=chart.id;
> amount
> --------
>    -75
>  21.13
>    -83
>   2.13
>    -83
>     21
>     50
>     50
>   2.26
>   -166
>     99
>   2.21
>    -83
>   -100
>     39
>     25
>    -70
>  -0.02
>     45
>  -0.05
>  -0.05
>  -0.04
>  -0.04
>     70
>     75
>     83
>     83
>    166
>     83
>    100
>   0.02
>   0.05
>   0.05
>   0.04
>   0.04
>    -21
>    -45
> -21.13
>  -2.13
>  -2.26
>  -2.21
>    -50
>    -50
>    -99
>    -39
>    -25
> (46 rows)
>
> accounting=# select  amount  from transactions, chart WHERE
> account=chart.id AND amount=amount;
> amount
> --------
>    -70
>     70
>    -75
>     75
>  -0.02
>   0.02
>    -45
>     45
> -21.13
>  21.13
>  -0.05
>   0.05
>    -83
>     83
>  -0.05
>   0.05
>  -2.13
>   2.13
>    -83
>     83
>    -21
>     21
>    -50
>     50
>  -0.04
>   0.04
>    -50
>     50
>  -2.26
>   2.26
>   -166
>    166
>    -99
>     99
>  -0.04
>   0.04
>  -2.21
>   2.21
>    -83
>     83
>   -100
>    100
>    -39
>     39
>    -25
>     25
> (46 rows)
>
>
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 8: explain analyze is your friend
>