sql - Combine two sql queries into one query

Question

How can I combine following 2 queries so that I can get two columns PAYMODE and PAYTYPE. Both queries are similar and for same table.Combine two sql queries into one query so that I don't need to execute two separate queries.

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

由于记录出现在源数据的不同行中，我很难在单个结果行中检索它们。您可以在一个查询中获得结果，该查询为您提供两行。尝试这个：

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。

Answer 2

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 中你可以这样做（不能在 DB2 中测试，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 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'