方法一(推荐):
1 2 3 4 5 6 7 8 9 | UPDATE 表2 SET 表2.C = ( SELECT B FROM 表1 WHERE 表1.A = 表2.A) WHERE EXISTS ( SELECT 1 FROM 表1 WHERE 表1.A = 表2.A); |
尤其注意最后的外层where条件尤为重要,是锁定其批量更新数据的范围。
方法二:
1 2 3 4 5 6 | MERGE INTO 表2 USING 表1 ON (表2.A = 表1.A) -- 条件是 A 相同 WHEN MATCHED THEN UPDATE SET 表2.C = 表1.B -- 匹配的时候,更新 |
grdk_dk_hkmx中yqksrq和yhkrq为空:
merge into grdk_dk_hkmx a
using (select a.f001 , a.f002 , a.f017 ,a.f024,a.f025 from wa350_hhgjj.gd_dk_hk a inner join grdk_dk_hkmx b on a.f001 = b.jkhtbh
and a.f002 = b.dqqc and a.f017 = b.ywlsh
where trim(a.f024) is not null and trim(b.yqksrq) is null) b
on (a.jkhtbh = b.f001 and a.dqqc = b.f002 and a.ywlsh = b.f017)
when matched then update set a.yqksrq = b.f024 , a.yhkrq = b.f025