传递空输入参数时，PLPGSQL函数不返回任何结果

Question

我有一个函数，它具有使用其中一个输入参数测试空值的条件。如果输入参数不为null，则执行sql statment，如果其null然后fit则执行最后一个SQL语句。

例如

当我执行该功能时 SELECT CAST(MD5(iml.udf_Extract_Shipment_HASHBYTESVALUES('SG160211304', '+00000', ''))

我希望执行第二个查询并获得结果集。

CREATE OR REPLACE FUNCTION iml.udf_extract_shipment_hashbytesvalues ( varchar, varchar,varchar
)
RETURNS TABLE (
  concatenatedfield text
) AS
$body$
DECLARE
    v_custpo  ALIAS FOR $1;
    v_shipqty ALIAS FOR $2;
    V_mfgpart ALIAS FOR $3;



BEGIN

    IF V_mfgpart IS NOT NULL OR V_mfgpart <> ' ' THEN

    RETURN QUERY

          SELECT 
            CAST(CASE WHEN order_no        IS NULL THEN '1' ELSE order_no        END AS VARCHAR(200)) ||
            CAST(CASE WHEN customer_po     IS NULL THEN '1' ELSE customer_po     END AS VARCHAR(200)) ||
            CAST(CASE WHEN cust_no         IS NULL THEN '1' ELSE cust_no         END AS VARCHAR(200)) ||
            CAST(CASE WHEN customer_name   IS NULL THEN '1' ELSE customer_name   END AS VARCHAR(200)) ||
            CAST(CASE WHEN vendor_no       IS NULL THEN '1' ELSE vendor_no       END AS VARCHAR(200)) ||
            CAST(CASE WHEN im_part_no      IS NULL THEN '1' ELSE im_part_no      END AS VARCHAR(200)) ||
            CAST(CASE WHEN order_branch    IS NULL THEN   1 ELSE order_branch    END AS VARCHAR(200)) ||
            CAST(CASE WHEN ship_frm_branch IS NULL THEN   1 ELSE ship_frm_branch END AS VARCHAR(200)) ||
            CAST(CASE WHEN ship_to_branch  IS NULL THEN   1 ELSE ship_to_branch  END AS VARCHAR(200)) ||
            CAST(CASE WHEN lent_order      IS NULL THEN '1' ELSE lent_order      END AS VARCHAR(200)) ||
            CAST(CASE WHEN order_type      IS NULL THEN '1' ELSE order_type      END AS VARCHAR(200)) ||
            CAST(CASE WHEN ship_qty        IS NULL THEN '1' ELSE ship_qty        END AS VARCHAR(200)) ||
            CAST(CASE WHEN inventory_type  IS NULL THEN '1' ELSE inventory_type  END AS VARCHAR(200)) ||
            CAST(CASE WHEN credit_code     IS NULL THEN '1' ELSE credit_code     END AS VARCHAR(200)) ||
            CAST(CASE WHEN tax_amt         IS NULL THEN   1 ELSE tax_amt         END AS VARCHAR(200)) ||
            CAST(CASE WHEN freight_in      IS NULL THEN '1' ELSE freight_in      END AS VARCHAR(200)) ||
            CAST(CASE WHEN freight_out     IS NULL THEN '1' ELSE freight_out     END AS VARCHAR(200)) ||
            CAST(CASE WHEN mfg_part        IS NULL THEN '1' ELSE mfg_part        END AS VARCHAR(200)) ||
            CAST(CASE WHEN description     IS NULL THEN '1' ELSE description     END AS VARCHAR(200))   
          FROM 
            iml.shipments
          WHERE customer_po = v_custpo AND ship_qty = v_shipqty  AND mfg_part = V_mfgpart;

    ELSEIF  V_mfgpart = '' OR  V_mfgpart IS NULL THEN
        RETURN QUERY
          SELECT 
            CAST(CASE WHEN order_no        IS NULL THEN '1' ELSE order_no        END AS VARCHAR(200)) ||
            CAST(CASE WHEN customer_po     IS NULL THEN '1' ELSE customer_po     END AS VARCHAR(200)) ||
            CAST(CASE WHEN cust_no         IS NULL THEN '1' ELSE cust_no         END AS VARCHAR(200)) ||
            CAST(CASE WHEN customer_name   IS NULL THEN '1' ELSE customer_name   END AS VARCHAR(200)) ||
            CAST(CASE WHEN vendor_no       IS NULL THEN '1' ELSE vendor_no       END AS VARCHAR(200)) ||
            CAST(CASE WHEN im_part_no      IS NULL THEN '1' ELSE im_part_no      END AS VARCHAR(200)) ||
            CAST(CASE WHEN order_branch    IS NULL THEN   1 ELSE order_branch    END AS VARCHAR(200)) ||
            CAST(CASE WHEN ship_frm_branch IS NULL THEN   1 ELSE ship_frm_branch END AS VARCHAR(200)) ||
            CAST(CASE WHEN ship_to_branch  IS NULL THEN   1 ELSE ship_to_branch  END AS VARCHAR(200)) ||
            CAST(CASE WHEN lent_order      IS NULL THEN '1' ELSE lent_order      END AS VARCHAR(200)) ||
            CAST(CASE WHEN order_type      IS NULL THEN '1' ELSE order_type      END AS VARCHAR(200)) ||
            CAST(CASE WHEN ship_qty        IS NULL THEN '1' ELSE ship_qty        END AS VARCHAR(200)) ||
            CAST(CASE WHEN inventory_type  IS NULL THEN '1' ELSE inventory_type  END AS VARCHAR(200)) ||
            CAST(CASE WHEN credit_code     IS NULL THEN '1' ELSE credit_code     END AS VARCHAR(200)) ||
            CAST(CASE WHEN tax_amt         IS NULL THEN   1 ELSE tax_amt         END AS VARCHAR(200)) ||
            CAST(CASE WHEN freight_in      IS NULL THEN '1' ELSE freight_in      END AS VARCHAR(200)) ||
            CAST(CASE WHEN freight_out     IS NULL THEN '1' ELSE freight_out     END AS VARCHAR(200)) ||
            CAST(CASE WHEN mfg_part        IS NULL THEN '1' ELSE mfg_part        END AS VARCHAR(200)) ||
            CAST(CASE WHEN description     IS NULL THEN '1' ELSE description     END AS VARCHAR(200))   
          FROM 
            iml.shipments
          WHERE customer_po = v_custpo AND ship_qty = v_shipqty  AND mfg_part IS NULL OR mfg_part = V_mfgpart
          ;

END IF;

END;
$body$
LANGUAGE 'plpgsql'
VOLATILE
CALLED ON NULL INPUT
SECURITY INVOKER
COST 100 ROWS 1000;

Answer 1

您传递的空字符串（非空）为mfgpart。所以第一个查询将被执行。仅当您将null作为mfgpart传递时，才会执行第二个查询。如果要在传递空字符串时执行第二个查询，请更改

IF V_mfgpart IS NOT NULL OR V_mfgpart <> ' ' THEN

到

IF V_mfgpart IS NOT NULL and V_mfgpart <> '' THEN

注意空格与空字符串

我怀疑你想要这个

create or replace function iml.udf_extract_shipment_hashbytesvalues (
    varchar v_custpo,
    varchar v_shipqty,
    varchar v_mfgpart
)
returns table (
  concatenatedfield text
) as
$body$
    select 
        cast(case when order_no        is null then '1' else order_no        end as varchar(200)) ||
        cast(case when customer_po     is null then '1' else customer_po     end as varchar(200)) ||
        cast(case when cust_no         is null then '1' else cust_no         end as varchar(200)) ||
        cast(case when customer_name   is null then '1' else customer_name   end as varchar(200)) ||
        cast(case when vendor_no       is null then '1' else vendor_no       end as varchar(200)) ||
        cast(case when im_part_no      is null then '1' else im_part_no      end as varchar(200)) ||
        cast(case when order_branch    is null then   1 else order_branch    end as varchar(200)) ||
        cast(case when ship_frm_branch is null then   1 else ship_frm_branch end as varchar(200)) ||
        cast(case when ship_to_branch  is null then   1 else ship_to_branch  end as varchar(200)) ||
        cast(case when lent_order      is null then '1' else lent_order      end as varchar(200)) ||
        cast(case when order_type      is null then '1' else order_type      end as varchar(200)) ||
        cast(case when ship_qty        is null then '1' else ship_qty        end as varchar(200)) ||
        cast(case when inventory_type  is null then '1' else inventory_type  end as varchar(200)) ||
        cast(case when credit_code     is null then '1' else credit_code     end as varchar(200)) ||
        cast(case when tax_amt         is null then   1 else tax_amt         end as varchar(200)) ||
        cast(case when freight_in      is null then '1' else freight_in      end as varchar(200)) ||
        cast(case when freight_out     is null then '1' else freight_out     end as varchar(200)) ||
        cast(case when mfg_part        is null then '1' else mfg_part        end as varchar(200)) ||
        cast(case when description     is null then '1' else description     end as varchar(200))   
    from 
        iml.shipments
    where
        customer_po = v_custpo and
        ship_qty = v_shipqty and
        (v_mfg_part is null or v_mfg_part = '' or mfg_part = v_mfgpart)
    ;
end;
$body$
language sql
volatile
called on null input
security invoker
cost 100 rows 1000;