Re: Conditional SQL Query

M.P.Dankoor wrote:
> devil live wrote:
>> how can I write a query to get right ingredients of a product basis on
>> production_no field
>>
>> such as;
>>
>> first check production_no if product_tree_special table if not found
>> then look at template table...
>>
>> What are your suggestions?
>>

I think M.P. Dankoor's suggestion is close but I believe the conditional
part you are looking for would make it into this -

select PRD.product_code
,PRD.product_name
,NULL::int AS production_no
,PTT.stock_code_to_make_product
,PTT.amount
from product PRD
,product_tree_template PTT
where PRD.product_code='searchcode'
AND PRD.product_code = case
when (select production_no from product_tree_special ts
where ts.product_code=PRD.product_code) is null
then PTT.product_code else '' end
UNION
select PRD.product_code
,PRD.product_name
,PTS.production_no
,PTS.stock_code_to_make_product
,PTS.amount
from product PRD
,product_tree_special PTS
where PRD.product_code='searchcode'
AND PRD.product_code = case
when (select production_no from product_tree_special ts
where ts.product_code=PRD.product_code) is not null
then PTS.product_code else '' end
ORDER BY 1,2,4

So if we entered the following -

INSERT INTO product VALUES ('one','test one');
INSERT INTO product VALUES ('two','test two');
INSERT INTO product_tree_special VALUES (1,'one','special list',1.1);
INSERT INTO product_tree_template VALUES ('two','template parts',2.2);

change both WHERE clauses to PRD.product_code='two' you will get -

two test two <null> template parts 2.2

then change both WHERE clauses to PRD.product_code='one' you will get -

one test one 1 special list 1.1

--

Shane Ambler
pgSQL(at)007Marketing(dot)com

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