PSQL and Variables - How do I use them in queries? 1

[dison123]

Hello,
I have written a simple query to generate appraisal details for Department members it is as follows.

select distinct
DP.DepartmentReference Reference,
DP.DepartmentName Name,
(select count(DM.PersonKey)DepartmentMembers from DepartmentMembershi DM
where DM.DepartmentKey = DP.DepartmentKey),
(select
count(DM.PersonKey) Appraised
from DepartmentMembershi DM,Appraisal AP
where
DM.DepartmentKey = DP.DepartmentKey and
DM.PersonKey = AP.PersonKeyAppraisee and
AP.AppraisalDate > (select
BP.StartDate
from
BudgetingPeriod BP
where BP.StartDate < CURDATE ( ) and BP.EndDate >= CURDATE ( )
and BP.Subcode = '') and
AP.AppraisalDate <= (select
BP.EndDate
from
BudgetingPeriod BP
where BP.StartDate < CURDATE ( ) and BP.EndDate >= CURDATE ( )
and BP.Subcode = '')
and AP.AppraisalStatus ='ACTU'
and AP.AppraisalType = 'ANNL'),
PD.DepartmentReference DeptAbove
from
Department DP

Left Outer Join Department PD
on
DP.DepartmentKeyDepar = PD.DepartmentKey


As you can see I only require Appraisal that occur in the current budged period. Can I assign the start and end dates of the current period to variables and use these instead in the query?
Thanks in advance

Pervasive 9.5.


David Ison

 

[mirtheil]

Variables are possible. How you do them depends on a few things including the actual interface and programming language. Generally speaking, you could use either parameters from your code or you can use a Parameterized Query.
Take the pseudo-code below for parameters from code:

string StartDate = "2008-04-06";
string sSQL = "select * from table where fldStart = '" + StartDate + "'";

A Parameterized Query is something more like:

PsqlParameter param;
param.value = "2008-04-06";
PsqlCommand cmd;
cmd.commandtext = "select * from table where fldStart = ?";
cmd.parameter.add (param);

I might have some better code once you post up the language and interface you're using.



Mirtheil
Certified Pervasive Developer
Certified Pervasive Technician

http://www.mirtheil.com

 

[dison123]

Thanks I understand both examples. Once again thankyou for your help.