MYSQL IF 字段包含 THIS 使其他字段 THAT

Question

我的表 1 中有一个名为 ITEM 的字段。如果 ITEM 包含 %USED-% (USED-) 那么我想制作它的 TIER1 Used Restaurant Equipment 所以它会相应地分组。

这是我当前的声明，我如何使用 IF 或 CASE 实现上述目标？

select 
    CT.TIER1, CT.TIER2
from
    trx.table1 MT
        LEFT JOIN
    trx.table2 CT1 ON MT.ITEM = CT1.ITEM
        LEFT JOIN
    trx.table3 CT ON CT1.WEB_NUM = CT.WEBNUMBER
GROUP BY CT.TIER1
LIMIT 0 , 15

当前输出:

TIER1                   TIER2
NULL                    NULL
Business Type           Ice Cream Equipment
Chinese Food Equipment  Ricers
Concession Equipment    Concession Accessories
Cooking Equipment       Fryers
Food Preparation        Food Preparation Supplies
Food Storage            Storage Racks
Food Warming Equipment  Hot Food Wells

我希望仍然有一些 NULL Tier1 和 Tier2，但我希望它也将 TIER1 显示为“二手餐厅设备”，类似于此:

TIER1                      TIER2
NULL                       NULL
Used Restaurant Equipment  NULL
Business Type              Ice Cream Equipment
Chinese Food Equipment     Ricers
Concession Equipment       Concession 

Answer 1

这应该是您要查找的内容:

   SELECT
       IF (MT.ITEM LIKE '%USED-%', 'Used Restaurant Equipment', CT.TIER1) AS TIER1,
       CT.TIER2
   FROM
       trx.table1 MT
           LEFT JOIN
       trx.table2 CT1 ON MT.ITEM = CT1.ITEM
           LEFT JOIN
       trx.table3 CT ON CT1.WEB_NUM = CT.WEBNUMBER
   GROUP BY
       IF (MT.ITEM LIKE '%USED-%', 'Used Restaurant Equipment', CT.TIER1)
   LIMIT 0 , 15