在SQL中使用基于CASE结果的不同WHERE子句

Question

我确实找到了类似问题的答案，但还不能完全理解。

我有一个带轮胎的MySQL桌子。轮胎记录由以下列组成：

1. 品牌
2. 宽度
3. 高度
4. 直径
5. 价

当宽度，高度和直径与某些值匹配时，我需要选择某些品牌的轮胎。如果没有，我需要选择其他部分重叠的轮胎品牌。

我需要在bogus-SQL中实现：

SELECT * FROM tyres
IF (width = 275 AND height = 55 AND diameter = 18)
    OR (width = 270 AND height = 55 AND diameter = 17)
    OR (width = 290 AND height = 45 AND diameter = 19)
THEN WHERE_CLAUSE = "WHERE brand = 'dunlop' OR brand = 'michelin' OR brand = 'vredestein'"
ELSE WHERE_CLAUSE = "WHERE brand = 'goodyear' OR brand = 'michelin' OR brand = 'ferrari'"

我尝试了很多符号如下，但（显然）不断收到语法错误＃1064：

SELECT * FROM tyres
CASE WHEN width = '275' AND height = '55' AND diameter = '18' THEN " WHERE brand = 'dunlop' OR brand = 'michelin' OR brand = 'vredestein'"
ELSE " WHERE brand = 'goodyear' OR brand = 'michelin' OR brand = 'ferrari'"

如何根据CASE语句的结果使用特定的WHERE子句？

Answer 1

尝试UNION ALL：

SELECT * FROM tyres
WHERE width = 275 AND height = 55 AND diameter = 18
AND (brand = 'dunlop' OR brand = 'michelin' OR brand = 'vredestein')
UNION ALL
SELECT * FROM tyres
WHERE width <> 275 OR height <> 55 OR diameter <> 18
AND (brand = 'goodyear' OR brand = 'michelin' OR brand = 'ferrari')

第一个SELECT是您帖子中的THEN部分，第二个SELECT是ELSE部分。