将两个sql查询合并为一个查询

Question

如何合并以下两个查询，以便我可以获得两列PAYMODE 和PAYTYPE。两个查询都是相似的，并且是相同的表。将两个sql查询组合成一个查询，以便我不需要执行两个单独的查询。

SELECT ETBL_DESC_TXT as PAYMODE 
FROM tedit 
WHERE CO_ID = 'CP' 
AND ETBL_TYP_ID = 'PMODE' 
AND ETBL_VALU_ID = 'RC' 


select ETBL_DESC_TXT as PAYTYPE 
FROM tedit 
WHERE CO_ID = 'CP' 
AND ETBL_TYP_ID = 'PTYPE' 
AND ETBL_VALU_ID = 'ER' 

Answer 1

你总是可以做到这一点

select 
    (
     SELECT ETBL_DESC_TXT 
     FROM tedit 
     WHERE CO_ID = 'CP' 
     AND ETBL_TYP_ID = 'PMODE' 
     AND ETBL_VALU_ID = 'RC' 
    ) as PAYMODE, 
    ( 
     select ETBL_DESC_TXT 
     FROM tedit 
     WHERE CO_ID = 'CP' 
     AND ETBL_TYP_ID = 'PTYPE' 
     AND ETBL_VALU_ID = 'ER' 
    ) as PAYTYPE 
from SYSIBM.SYSDUMMY1 

在SQL Server由于记录出现在不同的，你可以做到这一点（不能在DB2测试，抱歉）

 SELECT 
      max(case when ETBL_VALU_ID = 'RC' and ETBL_TYP_ID = 'PMODE' then ETBL_DESC_TXT else null end) as PAYMODE, 
      max(case when ETBL_VALU_ID = 'ER' and ETBL_TYP_ID = 'PTYPE' then ETBL_DESC_TXT else null end) as PAYTYPE 
     FROM tedit 
     where 
      CO_ID = 'CP' and 
      (
       (ETBL_VALU_ID = 'RC' and ETBL_TYP_ID = 'PMODE') or 
       (ETBL_VALU_ID = 'ER' and ETBL_TYP_ID = 'PTYPE') 
      ) 

Answer 2

源数据的行，我很难在单个结果行中检索它们。您可以在一个查询中得到两行结果。试试这个：

SELECT ETBL_DESC_TXT as PAYFIELD 
FROM tedit 
WHERE CO_ID = 'CP' AND (
     (ETBL_TYP_ID = 'PMODE' AND ETBL_VALU_ID = 'RC') 
    OR (ETBL_TYP_ID = 'PTYPE' AND ETBL_VALU_ID = 'ER') 
) 
ORDER BY ETBL_TYP_ID 

第一行将包含paymode，第二行将包含paytype。两个查询的

Answer 3

SELECT 'PAYMODE' as RowType,ETBL_DESC_TXT as PayValue 
FROM tedit 
WHERE CO_ID = 'CP' 
AND ETBL_TYP_ID = 'PMODE' 
AND ETBL_VALU_ID = 'RC' 

union all 

select 'PAYTYPE' as RowType, ETBL_DESC_TXT as PayValue 
FROM tedit 
WHERE CO_ID = 'CP' 
AND ETBL_TYP_ID = 'PTYPE' 
AND ETBL_VALU_ID = 'ER'