How can I use the IF in Firebird with a stored procedure? - sql

Question

I'm trying to write an IF statement in my stored procedure, but I have no idea how.
TIPO_DOCUMENTO can be 'FAC' or 'DEV', if TIPO_DOCUMENTO is 'FAC', I will use the total_neto, total_impuesto, total, costo and precio as is. But if I have 'DEV', I will need the negative values of those fields.
begin
/*FILTRO RANGO DE FECHA*/
IF (P_FECHA_DESDE='0' OR (P_FECHA_DESDE IS NULL) OR (P_FECHA_DESDE='')) THEN
V_FECHA_DESDE = CAST('01/01/1900' AS DATE);
ELSE
V_FECHA_DESDE = CAST(:P_FECHA_DESDE AS DATE);
IF (P_FECHA_HASTA='0' OR (P_FECHA_HASTA IS NULL)OR (P_FECHA_HASTA='')) THEN
V_FECHA_HASTA = CAST('12/31/3999' AS DATE);
ELSE
V_FECHA_HASTA = CAST(:P_FECHA_HASTA AS DATE);
/*FILTRO RANGO DE VENDEDORES*/
IF (P_VENDEDOR_DESDE IS NULL) THEN P_VENDEDOR_DESDE = '';
IF (P_VENDEDOR_HASTA IS NULL) THEN P_VENDEDOR_HASTA = LOWER('ZZZZZZZZZZZZZZZ');
IF (P_VENDEDOR_HASTA = '') THEN P_VENDEDOR_HASTA = LOWER('ZZZZZZZZZZZZZZZ');
IF (NOT ((P_VENDEDOR_DESDE = '') AND (P_VENDEDOR_HASTA = LOWER('ZZZZZZZZZZZZZZZ')))) THEN
IF (P_VENDEDOR_DESDE = P_VENDEDOR_HASTA) THEN
V_WHERE = V_WHERE || ' AND (VEN.VENDEDOR_CODIGO = '''||P_VENDEDOR_DESDE||''')';
ELSE
V_WHERE = V_WHERE || ' AND (VEN.VENDEDOR_CODIGO BETWEEN '''||P_VENDEDOR_DESDE||''' AND '''||P_VENDEDOR_HASTA||''')';
/*CICLO DE LA CONSULTA SQL*/
FOR SELECT
a.tipo_documento,
a.documento,
b.nombre as vendedor,
c.producto_codigo,
c.producto_nombre as descripcion,
c.cantidad,
d.departamento_codigo,
c.deposito_codigo,
(c.descuento_unitario * c.cantidad) + (c.descuento_unitario_2 * c.cantidad) + (c.descuento_unitario_3 * c.cantidad) +(c.descuento_unitario_4 * c.cantidad) as total_descuento,
c.total_neto,
c.total_impuesto,
c.total,
a.cliente_codigo,
a.cliente_nombre,
e.direccion,
estado.nombre,
ciudad.nombre,
c.costo_unitario * c.cantidad as costo,
c.precio_unitario * c.cantidad as precio
from ventas a
join vendedores b
on a.vendedor_codigo = b.codigo
join ventas_detalles c
on a.correlativo = c.correlativo_principal
join productos_terminados d
on d.codigo_producto = c.producto_codigo
join clientes e
on a.cliente_codigo = e.codigo
join ubicacion_geografica estado
on estado.codigo = e.estado
and estado.tipo = 'E'
join ubicacion_geografica ciudad
on ciudad.codigo = e.ciudad
and ciudad.tipo = 'C'
where a.fecha_emision between :V_FECHA_DESDE and :V_FECHA_HASTA
INTO
:TIPO_DOC,
:NUM_DOC,
:VENDEDOR_NOMBRE,
:PRODUCTO_CODIGO,
:PRODUCTO_NOMBRE,
:CANTIDAD,
:DEPARTAMENTO,
:DEPOSITO,
:DESCUENTO,
:TOTAL_NETO,
:TOTAL_IMPUESTO,
:TOTAL,
:CLIENTE_CODIGO,
:CLIENTE_NOMBRE,
:CLIENTE_DIRECCION,
:ESTADO,
:CIUDAD,
:COSTO,
:PRECIO
do
begin
if (TIPO_DOC = 'DEV') then
total_neto = -total_neto ;
total_impuesto = -total_impuesto ;
total = -total ;
costo = -costo ;
precio = -precio;
suspend;
end
end
Now I can only get the negative values, regardless of whether I have FAC or DEV.

Answer 1

Your if is syntactically wrong for what I think you want to do. The indentation of the following suggests that all those statements should depend on the if condition:
if (TIPO_DOC = 'DEV') then
total_neto = -total_neto ;
total_impuesto = -total_impuesto ;
total = -total ;
costo = -costo ;
precio = -precio;
In reality only the first statement after the if belongs to the if condition. In other words, it is actually
if (TIPO_DOC = 'DEV') then
total_neto = -total_neto ;
total_impuesto = -total_impuesto ;
total = -total ;
costo = -costo ;
precio = -precio;
If you want all those statements to depend on the if, you need to define a block using begin and end:
if (TIPO_DOC = 'DEV') then
begin
total_neto = -total_neto ;
total_impuesto = -total_impuesto ;
total = -total ;
costo = -costo ;
precio = -precio;
end
See also IF ... THEN ... ELSE in the Firebird 2.5 Language Reference.

Answer 2

Not an answer, just an advice, using syntactic highlighting.
FOR SELECT
....
do
if (TIPO_DOC = 'DEV') then
total_neto = -total_neto ;
total_impuesto = -total_impuesto ;
total = -total ;
costo = -costo ;
precio = -precio;
This code has few problems with me.
If within loop - often it may slow down execution. So if IF condition is not dependent upon loop data - if it is invariant - it might make sense to move If outside of loop.
Future compatibility - what would you procedure do if for example TIPO_DOCUMENTO = 'BE-BE-BE'? Should not happen today? But it can happen tomorrow as new functions would be added to the program. It even can happen today because of some bug.
Personally i would do it different way:
DECLARE VARIABLE COEFF SMALLINT;
....
COEFF = CASE TIPO_DOC
WHEN 'DEV' THEN -1
WHEN 'FAC' THEN +1
ELSE :COEFF / 0 /* generate error if prohibited value */
END;
-- shorthand
-- COEFF = DECODE( TIPO_DOC, 'DEV',-1, 'FAC',+1, :COEFF / 0 );
FOR SELECT....
DO
total_neto = COEFF*total_neto ;
total_impuesto = COEFF*total_impuesto;
....
More strange things: P_VENDEDOR_DESDE = ''; - thus this variable is some text type, like VarChar or CHAR or BLOB SUB_TYPE TEXT.
Then why VEN.VENDEDOR_CODIGO BETWEEN '''||P_VENDEDOR_DESDE||''' AND '''||P_VENDEDOR_HASTA||''' ???
Why not just VEN.VENDEDOR_CODIGO BETWEEN P_VENDEDOR_DESDE AND P_VENDEDOR_HASTA ?