personalt wrote:
> I read that page last night.. That sounded like what I wanted to do but I
> had no idea how to get my simple query to be a parameterized query. That
> is really what I was looking for help on.
>
> select kwhcost1 from applications;
>
> SELECT monitordata_hourly.deviceaddress,
> Round(Sum(monitordata_hourly.ch1kwh),3) AS SumOfch1kwh,
> Round(Sum(monitordata_hourly.ch1kwh),3)*.19 AS SumOfch1kwh_cost
> FROM monitordata_hourly
> Where monitordata_hourly.deviceaddress=142265 and
> (datetime(monitordata_hourly.date))>=datetime('now', 'localtime', '-30
> days')
> Group by monitordata_hourly.deviceaddress
So you run the first query (select kwhcost1 from applications;) and retrieve
the KWH value into a variable in your program. Then you prepare (using
sqlite3_prepare[_v2]) your second query with a parameter:
SELECT monitordata_hourly.deviceaddress,
Round(Sum(monitordata_hourly.ch1kwh),3) AS SumOfch1kwh,
Round(Sum(monitordata_hourly.ch1kwh),3)* ? AS SumOfch1kwh_cost
FROM monitordata_hourly
Where monitordata_hourly.deviceaddress=142265 and
(datetime(monitordata_hourly.date))>=datetime('now', 'localtime', '-30
days')
Group by monitordata_hourly.deviceaddress
Note the question mark in place of hardcoded .19. You may also want to
parameterize other hardcoded constants while you are at it. Anyway, next you
use a suitable sqlite3_bind_* flavor to bind the parameter (sqlite3_bind_double
in your case), several calls to sqlite3_step to iterate over the resultset, and
finally sqlite3_reset (if you want to reuse the query) or sqlite3_finalize (if
you are done with it).
Igor Tandetnik
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