Question

您是否可以在以下SQL调用中看到限制此特定部分的结果数量的方法：

OR (u1 != '2' AND u2 != '2' AND u3 != '2' AND m.membership_id = 1 AND m.aff IN (SELECT id FROM members WHERE id != 2 AND membership_id = 1 OR jv > 0)))

我想将匹配数限制为一个确切的数字，例如150

完整的SQL是：

SELECT DISTINCT mid, did FROM product_access, members AS m 
WHERE mid = m.id AND m.active = 1 
      AND m.suspended = 0 
      AND (u1 = '2' OR u2 = '2' OR u3 = '2' OR (u1 != '2' AND u2 != '2' AND u3 != '2' AND m.membership_id = 1 AND m.aff IN (SELECT id FROM members WHERE id != 2 AND membership_id = 1 OR jv > 0))) GROUP BY mid

因此，结果应该包括所有u1 = '2'，u2 = '2'所有地方u3 = '2'所有地方，但只有150所在地：

(u1 != '2' AND u2 != '2' AND u3 != '2' AND m.membership_id = 1 AND m.aff IN (SELECT id FROM members WHERE id != 2 AND membership_id = 1 OR jv > 0))

Answer 1

您始终可以从查询的每个部分创建子查询，并将其限制为n个最顶层条目。

根据我的理解，这样的事情应该足够了：

SELECT mid, did FROM(
SELECT DISTINCT mid, did FROM product_access, members AS m 
WHERE mid = m.id AND m.active = 1 
      AND m.suspended = 0 
      AND (u1 = '2' OR u2 = '2' OR u3 = '2')

UNION SELECT TOP 150 DISTINCT mid, did FROM product_access, members AS m 
WHERE mid = m.id AND m.active = 1 
     AND m.suspended = 0 
     AND (u1 != '2' AND u2 != '2' AND u3 != '2' AND m.membership_id = 1 AND m.aff IN (SELECT id FROM members WHERE id != 2 AND membership_id = 1 OR jv > 0))

) GROUP BY mid

Answer 2

如果SQL SERVER然后使用TOP，请MY SQL然后使用LIMIT。

SQL-Server

SELECT TOP 10 * FROM MyTable;

我的SQL

SELECT * FROM MyTable LIMIT 10;

如何限制SQL查询特定部分的结果数？

2 个答案: