所以我有这样的MySQL凡,极限输出
SELECT * FROM table WHERE id IN (1,2,3) LIMIT 10
查询是否有可能限制输出的数量每个数组元素像
SELECT * FROM table WHERE id 1 LIMIT 10
SELECT * FROM table WHERE id 2 LIMIT 10
SELECT * FROM table WHERE id 3 LIMIT 10
所以我有这样的MySQL凡,极限输出
SELECT * FROM table WHERE id IN (1,2,3) LIMIT 10
查询是否有可能限制输出的数量每个数组元素像
SELECT * FROM table WHERE id 1 LIMIT 10
SELECT * FROM table WHERE id 2 LIMIT 10
SELECT * FROM table WHERE id 3 LIMIT 10
是的,你可以做它使用变量:
SELECT *
FROM (
SELECT *,
@seq := IF(id = @id, @seq + 1,
IF(@id := id, 1, 1)) AS seq
FROM table
CROSS JOIN (SELECT @seq := 0, @id := 0) AS vars
WHERE id IN (1,2,3)
ORDER BY id) AS t
WHERE t.seq <= 10
完美。谢谢 –
如果你害怕的MySQL变量(我),你也可以使用一个UNION
曲ery:
(SELECT * FROM table WHERE id = 1 LIMIT 10)
UNION ALL
(SELECT * FROM table WHERE id = 2 LIMIT 10)
UNION ALL
(SELECT * FROM table WHERE id = 3 LIMIT 10)
IN数组是动态生成的并且处理非常大的数据集。这个查询会有性能瓶颈? –
然后@Giorgos的答案可能是你在找什么。 –
请注意,没有ORDER BY的LIMIT是相当无意义的。 – Strawberry