As a followup to my previous posting:

This works:

q.sql = "SELECT 69.1 * LATITUDE - 40.7409 AS DISTANCE, NAME FROM
WEBDATA"

This does not work - give an -804 error
q.sql = "SELECT 69.1 * LATITUDE - :lat1 AS DISTANCE, NAME FROM
WEBDATA
q.params["lat1"] := 40.7409


--- In firebird-support@yahoogroups.com, Helen Borrie <helebor@...>
wrote:

>
> At 08:25 AM 10/01/2009, irajoel2000 wrote:
> >The error code I get is -804 which has a number of meanings listed
> >in the appendix of Helen's Firebird Book. I have no idea how to
> >interpret them.
>
> Those are all errors to do the with the structures being passed

across the API to the DSQL parser. In this case, your mistake is in
your confusion of *parameters* with *variables*. Parameters are not
variables, so you cannot refer to two parameters as though they were
a single variable.

>
> I can't comment on whether your query will return a correct result,

as I don't know the zipcode algorithm. It will be up to you to check
that side of things to verify your expression calculations.

>
> To make your query correct, you need ONE PARAMETER FOR EACH VALUE

THAT IS TO BE SUBSTITUTED. (The FB Book actually emphasises this in
several places!!)

>
> lat = 40.9999
> lon = -77.876
>
> SELECT ((69.1*(:lat1-LATITUDE))*(69.1*(:lat2-LATITUDE))+(69.1*

(:lon1-

> (LONGITUDE))*COSINE)*(69.1*(:lon2-(LONGITUDE))*COSINE)) AS

DISTANCE,

> LATITUDE, LONGITUDE, COSINE, WEBTYPE, NAME, NOTE, IDNUM,
> TYPE1,NAME2,CONTACT,ADDRESS1,ADDRESS2,CITY,STATE,ZIP,EDATE, PHONE,

EXT,

> HOTLINE, FAX, INTERNET, DESCRIPT, WWWEB, GIVE_ADDR, WEBSITE FROM
> hotline WHERE WEBSITE = 'Y' AND CLOSED = 'N' ORDER BY WEBTYPE, NAME
>
> Firebird's parameters are not named. They are determined by the

order in which they are prepared. When your application passes the
statement across the API to be prepared, it looks like this:

>
> SELECT ((69.1*(?-LATITUDE))*(69.1*(?-LATITUDE))+(69.1*(?-
> (LONGITUDE))*COSINE)*(69.1*(?-(LONGITUDE))*COSINE)) AS DISTANCE,
> LATITUDE, LONGITUDE, COSINE, WEBTYPE, NAME, NOTE, IDNUM,
> TYPE1,NAME2,CONTACT,ADDRESS1,ADDRESS2,CITY,STATE,ZIP,EDATE, PHONE,

EXT,

> HOTLINE, FAX, INTERNET, DESCRIPT, WWWEB, GIVE_ADDR, WEBSITE FROM
> hotline WHERE WEBSITE = 'Y' AND CLOSED = 'N' ORDER BY WEBTYPE, NAME
>
> Your data access layer prepares 4 SQLVAR structures in the SQLDA,

hence the error you are getting from your garbage SQLDA - with at
least one of the following errors returning the error status array:

>
> -804|335544583|dsql_sqlda_err|SQLDA missing or incorrect version,

or incorrect number/type of variables

>
> -804|335544584|dsql_var_count_err|Count of read-write columns does

not equal count of values

>
> -804|335544713|dsql_sqlda_value_err|Incorrect values within SQLDA

structure

>
> Given the syntax you provide, I'm assuming you are using Delphi.

Most (if not all) Delphi access layers provide that mechanism
for "naming" parameters, that operates ONLY within your client
application. You have four parameters (not two) so your application
needs to be given four names. At execution time, your application
has to assign *values* to each parameter in the prepared statement.
For example (for most Delphi interfaces):

> ...
> with MyDataset do
> begin
> ParamByName('lat1').AsExtended := 40.9999;
> ParamByName('lat2').AsExtended := 40.9999;
> ParamByName('lon1').AsExtended := -77.876;
> ParamByName('lon2').AsExtended := -77.876;
> end;
> ...
>
> ./heLen
>