上一栏的Concat

Question

我有办法从逻辑确定的前一列中合并一列吗？

    
    select
    if(p.mfg is not null , p.mfg, 'Private') as MFG,
    concat(MFG, " ",p.sku) as TITLE
    from product p

Answer 1

您可以使用CASE语句，例如

select
if(p.mfg is not null , p.mfg, 'Private') as MFG,
concat(case when p.mfg is not null then p.mfg else 'Private' end, " ",p.sku) as TITLE
from product p

（OR）使用inline view

select MFG, concat(MFG, " ", sku) as TITLE
from (select if(p.mfg is not null , p.mfg, 'Private') as MFG, sku from product p
    ) tab