查询以查找sql​​ server

Question

我有一个包含一些列的表。我想编写一个迭代遍历每一行的查询，查找与所选行中的列匹配的所有行的总数，并查找与2列匹配的所有行的计数。使用这两个值，我想找到百分比差异并将它们打印为column1，percentage（query1（column2）/ query2（column2和column3））。

以下是我写的查询

    SELECT DISTINCT (t2.column1)
    ,(
        SELECT count(DISTINCT column2)
        FROM table1 t1
        WHERE t1.column1 = t2.column1
        ORDER BY column2
        ) AS total_count
    ,(
        SELECT count(DISTINCT column2)
        FROM table1 t1
        WHERE t1.column1 = t2.column1
            AND column3 IN (
                10
                ,20
                )
        ORDER BY column1
            ,column2
            ,column3
        ) AS column3_count
FROM table1 t2;

以上查询有效，但需要花费大量时间来处理。

我希望它为

   SELECT DISTINCT (column1)
    ,percentage(query1 that matches ALL rows WITH column1 / query2 that match ALL rows WITH column1
        AND SOME other CONSTRAINT)
FROM TABLE t1

我也想优化上面的查询。请让我知道

由于

Answer 1

我认为你只想要条件聚合。对于计数：

select t1.column1,
       count(distinct column2) as num_column2,
       count(distinct case when column3 in (10, 20) then column2 end) as num_column2_column3
from table1 t1
group by t1.column1;

我不了解百分比的计算方法，但似乎是基于这些数字。

Answer 2

select t1.column1,
       count(distinct column2) as num_column2,
       count(distinct case when column3 in (10, 20) then column2 end) as num_column2_column3
from table1 t1
group by t1.column1;