mysql - mysql - 当计数大于零时选择true

Question

我有以下查询。

SELECT COUNT( * ) AS offer_count
  FROM restaurants_offers
WHERE DATE( NOW( ) ) 
   BETWEEN date_start
   AND date_end
AND restaurant_id =1

现在，当 count 大于零时，我想选择trueelse false，而不是 count 作为查询结果。怎么做？

Answer 1

试试这个：

SELECT IF(COUNT(*) > 0, 'true', 'false') AS NewResult
  FROM restaurants_offers
 WHERE (DATE(NOW())  BETWEEN date_start AND date_end) AND 
       restaurant_id = 1

Answer 2

SELECT COUNT( * ) > 0 AS has_offers
  FROM restaurants_offers
WHERE DATE( NOW( ) ) 
   BETWEEN date_start
   AND date_end
AND restaurant_id =1

Answer 3

SELECT case when COUNT(*) > 0 
            then 1
            else 0
       end AS offer_count
FROM restaurants_offers
WHERE DATE( NOW( ) ) 
BETWEEN date_start
AND date_end
AND restaurant_id =1

或者如果你需要的话true和false

SELECT case when COUNT(*) > 0 
            then 'true'
            else 'false'
       end AS offer_count
...