Sql 加入Db2查询
我使用内部联接联接了两个表。这里表Sql 加入Db2查询,sql,db2,Sql,Db2,我使用内部联接联接了两个表。这里表TPREG的主键是co\u id和pol\u id SELECT (SELECT etbl_desc_txt FROM uding604.tedit e WHERE etbl_typ_id = 'PITCD' AND co_id = 'CP' AND etbl_valu_id = p.pol_ind_typ_cd) pol_ind_typ_cd, (SELECT etbl_desc_
TPREG
的主键是co\u id
和pol\u id
SELECT (SELECT etbl_desc_txt
FROM uding604.tedit e
WHERE etbl_typ_id = 'PITCD'
AND co_id = 'CP'
AND etbl_valu_id = p.pol_ind_typ_cd) pol_ind_typ_cd,
(SELECT etbl_desc_txt
FROM uding604.tedit e
WHERE etbl_typ_id = 'PAYT'
AND co_id = 'CP'
AND etbl_valu_id = p.POL_BILL_TYP_CD) POL_BILL_TYP_CD,
POL_PAC_DRW_DY,
(SELECT etbl_desc_txt
FROM uding604.tedit e
WHERE etbl_typ_id = 'PAYM'
AND co_id = 'CP'
AND etbl_valu_id = p.POL_BILL_MODE_CD) POL_BILL_MODE_CD,
t.SOURCE_CD
FROM uding604.tpol p,
uding604.TPREG t
WHERE p.co_id = t.co_id
AND p.pol_id = t.pol_id
AND p.co_id = 'CP'
AND p.pol_id = '000000011'
AND t.co_id = 'CP'
AND t.pol_id = '000000011'
如何使此查询更简单
请指导。您可以将子查询Yes转换为联接:
SELECT e1.etbl_desc_txt as pol_ind_typ_cd,
e2.etbl_desc_txt as POL_BILL_TYP_CD,
POL_PAC_DRW_DY,
e3etbl_desc_txt as POL_BILL_MODE_CD,
t.SOURCE_CD
FROM uding604.tpol p,
uding604.TPREG t,
uding604.tedit e1,
uding604.tedit e2,
uding604.tedit e3
WHERE p.co_id = t.co_id
AND p.pol_id = t.pol_id
AND p.co_id = 'CP'
AND p.pol_id = '000000011'
AND t.co_id = 'CP'
AND t.pol_id = '000000011'
AND e1.etbl_typ_id = 'PITCD'
AND e1.co_id = 'CP'
AND e1.etbl_valu_id = p.pol_ind_typ_cd
AND e2.etbl_typ_id = 'PAYT'
AND e2.co_id = 'CP'
AND e2.etbl_valu_id = p.POL_BILL_TYP_CD
AND e3.etbl_typ_id = 'PAYM'
AND e3.co_id = 'CP'
AND e3.etbl_valu_id = p.POL_BILL_MODE_CD
查询在select
子句上更清晰,但在Where
子句上模糊
我们可以做的是继续使用ANSI连接语法:
SELECT e1.etbl_desc_txt as pol_ind_typ_cd,
e2.etbl_desc_txt as POL_BILL_TYP_CD,
POL_PAC_DRW_DY,
e3etbl_desc_txt as POL_BILL_MODE_CD,
t.SOURCE_CD
FROM uding604.tpol p
JOIN uding604.TPREG t on (p.co_id = t.co_id AND p.pol_id = t.pol_id)
JOIN uding604.tedit e1 on (e1.etbl_valu_id = p.pol_ind_typ_cd and e1.co_id = p.co_id)
JOIN uding604.tedit e2 on (e2.etbl_valu_id = p.POL_BILL_TYP_CD and e2.co_id = p.co_id)
JOIN uding604.tedit e3 on (e3.etbl_valu_id = p.POL_BILL_MODE_CD and e3.co_id = p.co_id)
WHERE p.co_id = 'CP'
AND p.pol_id = '000000011'
AND t.co_id = 'CP'
AND t.pol_id = '000000011'
AND e1.etbl_typ_id = 'PITCD'
AND e2.etbl_typ_id = 'PAYT'
AND e3.etbl_typ_id = 'PAYM'
现在更清楚你想要什么了
注1。您可以尝试删除
AND t.co_id = 'CP'
AND t.pol_id = '000000011'
因为逻辑不是必需的
注2。您必须测试这些查询是否返回与您的查询相同的结果
注3。您应该始终使用ANSI JOIN语法,这将在您不期望的情况下对您有所帮助