mysql - 如何简化 SQL 查询中的可重复模式？

Question

是否可以简化:

SELECT GREATEST(a,b)
FROM my_table 
WHERE GREATEST(a,b) > 25

类似于:

SELECT GREATEST(a,b) AS max_a_b 
FROM my_table 
WHERE max_a_b > 25

这个尝试返回:

Unknown column 'max_a_b' in 'where clause'

Answer 1

SELECT GREATEST(a,b) AS max_a_b 
FROM my_table 
HAVING max_a_b > 25

如果您使用 having 子句，您的别名在 where level 不存在。