更新如果列不爲空，如果爲空，然後離開在零

Question

我有以下SQL：

UPDATE TableA 
SET first_name = 'AAA', 
    last_name = 'BBB', 
    address1 = '123', 
    address2 = 'Fake St.,', 
    phone = '1234567', 
    id = '11223344' 

我應該使用只更新每個列如果它不爲空？

Answer 1

update tableA 
set first_name = case when first_name is null then null else 'aaa' end, 
last_name = case when last_name is null then null else 'bbb' end, 
... 

Answer 2

只是另一種方法更簡潔一些（少可讀性）：

UPDATE TableA 
SET first_name = left( 'AAA' + first_name, 3) , 
    last_name = left( 'BBB' + last_name, 3) , 
    address1 = left( '123' + address1, 3) , 
    address2 = left( 'Fake St.,' + address2, len('Fake St.,')) , 
    ...