我编写了这两个查询，第一个是保留重复项，第二个是删除它们
有人知道一个更有效的方法来实现这一点吗？
查询是针对mssql的，返回前3个值
1-

SELECT TMP.entity_id, TMP.value
FROM(
    SELECT TAB.entity_id, LEAD(TAB.entity_id, 3, 0) OVER(ORDER BY TAB.entity_id, TAB.value) AS next_id, TAB.value
    FROM mytable TAB
) TMP
WHERE TMP.entity_id <> TMP.next_id

2-

SELECT TMP.entity_id, TMP.value
FROM(
    SELECT TMX.entity_id, LEAD(TMX.entity_id, 3, 0) OVER(ORDER BY TMX.entity_id, TMX.value) AS next_id, TMX.value
    FROM(
        SELECT TAB.entity_id, LEAD(TAB.entity_id, 1, 0) OVER(ORDER BY TAB.entity_id, TAB.value) AS next_id, TAB.value, LEAD(TAB.value, 1, 0) OVER(ORDER BY TAB.entity_id, TAB.value) AS next_value
        FROM mytable TAB
    ) TMX
    WHERE TMP.entity_id <> TMP.next_id OR TMX.value <> TMX.next_value
) TMP
WHERE TMP.entity_id <> TMP.next_id

例子：
表格：

entity_id   value
---------   -----
1           9
1           11
1           12
1           3
2           25
2           25
2           5
2           37
3           24
3           9
3           2
3           15

结果查询1（实体2的25出现两次）：

entity_id   value
---------   -----
1           9
1           11
1           12
2           25
2           25
2           37
3           9
3           15
3           24

结果查询2（对于实体2，25只出现一次）：

entity_id   value
---------   -----
1           9
1           11
1           12
2           5
2           25
2           37
3           9
3           15
3           24