SQL - 如何計算列的唯一組合

Question

我不確定這是否可行，但我想計算表中唯一值的數量。 我知道要計算我所做的唯一文件夾ID 的數量：

select count(folderid) from folder

但我想要計算文件夾表中文件夾 ID 和用戶 ID 的唯一組合的數量。 有沒有辦法做到這一點？

Answer 1

select count(*) from (
  select distinct folderid, userid from folder
)

Answer 2

select count(*) from (
    select folderId, userId
    from folder
    group by folderId, userId
) t

Answer 3

這將為您提供唯一的folderid和userid組合的計數：

SELECT count(*)
  FROM (
        SELECT DISTINCT
               folderid,
               userid
          FROM folder
);

希望能幫助到你...

Answer 4

選擇 super_group_account_id，
sub_group_account_id,
Concat (super_group_account_id, ' ', sub_group_account_id),
( Concat (super_group_account_id, ' ', sub_group_account_id)) ( Concat (super_group_account_id, ' ', sub_group_account_id))
FROM super_sub_group_mapping
GROUP BY Concat (super_group_account_id, ' ', sub_group_account_id)
( Concat (super_group_account_id, ' ', sub_group_account_id)) > 1 HAVING ( Concat (super_group_account_id, ' ', sub_group_account_id)) > 1

Answer 5

我想你可以嘗試將select語句與文件夾ID分組

例如。

我有一張桌子

folderid用戶標識

1 11

1 11

2 12

2 12

3 13

3 13

查詢是

select count(folderid) from testtable group by folderid, userid

Answer 6

select APPRSL_ID,SECTION_ID, count(APPRSL_ID||SECTION_ID)
from REMARKSBYEACHSECTION 
group by APPRSL_ID,SECTION_ID
having count(APPRSL_ID||SECTION_ID)>1 ;