所以我有以下两个更新语句:
UPDATE table1 SET column1_new = "1" WHERE column1_old IS NOT NULL
UPDATE table1 SET column2_new = "2" WHERE column2_old IS NOT NULL
有没有办法在一个数据库调用中执行此操作?
你可以做:
UPDATE table1
SET column1_new = (CASE WHEN column1_old IS NOT NULL THEN 1 ELSE column1_new),
column2_new = (CASE WHEN column2_old IS NOT NULL THEN 2 ELSE column2_new)
WHERE column1_old IS NOT NULL OR column2_old IS NOT NULL;
但是,我认为使用update
查询更简单。
在这种特殊情况下,您可能会发现nvl2
函数很有用,但您无法避免在where条件中使用or
。
update table1 set column1_new = nvl2(column1_old, 1, column1_new),
column2_new = nvl2(column2_old, 2, column2_new)
where column1_old is not null or column2_old is not null;