Re: Conditional SQL Query

I think that the simplest solution is to use an union e.g:

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 1 = 1
AND PRD.product_code = PTT.product_code
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 1 = 1
AND PRD.product_code = PTS.product_code
ORDER BY 1,2,4

I've added an order by the columns 1,2 and 4 (just guessing),
note that this particular solution uses positional ordering, i.e no
column names.

Mario

devil live wrote:
>
> I want to write sql statement about product, product_tree_special,
> product_tree_template
>
> product has
> product_code varchar(20) PRIMARY KEY,
> product_name varchar(20)
>
> product_tree_template has
> product_code varchar(20) PK,
> stock_code_to_make_product(20) PK,
> amout float4
>
> product_tree_spcial has
> production_no serial,
> product_code varchar(20) PK,
> stock_code_to_make_product(20) PK,
> amout float4
>
>
>
> NOW : product_tree_template table is the default table for production
> ingredients of the PRODUCT
>
> but sometimes my customer using special product_tree table for some
> production_no
>
> 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?
>
>
>
> PS: I do not wanna write PL functions for this...
>
> Thanks
>
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