select distinct count

相關問題 & 資訊整理

select distinct count

If you want to get the total count for each user, then you will use: select user_id, count(distinct video_id) from data group by user_id;. Then if you want to get the total video_ids then you will wrap this inside of a subquery: select sum(cnt) TotalVide,You can use this: SELECT COUNT(*) FROM (SELECT DISTINCT column_name FROM table_name) AS temp;. This is much faster than: COUNT(DISTINCT column_name). , When you do select distinct count(id) then you are basically doing: select distinct cnt from (select count(id) as cnt from t) t;. Because the inner query only returns one row, the distinct is not doing anything. The query counts the number of rows in the, Distinct is not required in your SQL ,as you are going to get only result, count(*) without group by clause returns, count of all rows within that table. Hence try this : select count(*) from table1. Distinct is used for finding distinct values from a gr, Query select count(distinct a) will give you number of unique values in a. While query select distinct count(a) will give you list of unique counts of values in a. Without grouping it will be just one line with total count. See following example create t,"IS NOT NULL" 是"這個欄位不是空白" 的意思。 COUNT 和DISTINCT 經常被合起來使用,目的是找出表格中有多少筆不同的資料(至於這些資料實際上是什麼並不重要)。舉例來說,如果我們要找出我們的表格中有多少個不同的Store_Name,我們就鍵入,. SELECT COUNT (DISTINCT Store_Name) FROM Store_Information;. 結果: ... ,定义和用法. 可以一同使用DISTINCT 和COUNT 关键词,来计算非重复结果的数目。 语法. SELECT COUNT(DISTINCT column(s)) FROM table. 例子. 注意:下面的例子仅适用于ORACLE 和Microsoft SQL server,不能用于Microsoft Access。 "Orders"表:. Company, OrderNumber. IBM, 3532. W3School, 2356. Apple, 4698. ,SELECT COUNT(DISTINCT Country) FROM Customers;. Try it Yourself ». Note: The example above will not work in Firefox and Microsoft Edge! Because COUNT(DISTINCT column_name) is not supported in Microsoft Access databases. Firefox and Microsoft Edge are usin,SQL SELECT DISTINCT with COUNT on ROWS or on one columns. ,Count all the DISTINCT program names by program type and push number. SELECT COUNT(DISTINCT program_name) AS Count, program_type AS [Type] FROM cm_production WHERE push_number=@push_number GROUP BY program_type. DISTINCT COUNT(*) will return a row for eac

相關軟體 UR Browser 資訊

UR Browser
UR Browser 讓您個性化您的瀏覽器,安全地瀏覽網頁,並享受噸的偉大功能!下載 UR Browser,一個尊重用戶隱私的快速和免費的網頁瀏覽器。 100%歐洲,內置 VPN 和廣告攔截器。使用 UR.UR Browser 保護您的數據和隱私功能:所有文件都被病毒掃描 您下載的文件會自動掃描病毒和惡意軟件.您立即收到可疑網站的警報 網站懷疑有網絡釣魚,惡意軟件或偽造消息會在您之前自動觸發警... UR Browser 軟體介紹

select distinct count 相關參考資料
MySQL Select Distinct Count - Stack Overflow

If you want to get the total count for each user, then you will use: select user_id, count(distinct video_id) from data group by user_id;. Then if you want to get the total video_ids then you will wr...

https://stackoverflow.com

performance - postgresql COUNT(DISTINCT ...) very slow - Stack ...

You can use this: SELECT COUNT(*) FROM (SELECT DISTINCT column_name FROM table_name) AS temp;. This is much faster than: COUNT(DISTINCT column_name).

https://stackoverflow.com

select distinct count(id) vs select count(distinct id) - Stack ...

When you do select distinct count(id) then you are basically doing: select distinct cnt from (select count(id) as cnt from t) t;. Because the inner query only returns one row, the distinct is not doi...

https://stackoverflow.com

sql - What exactly does SELECT DISTINCT(COUNT(*)) do? - Stack Overflow

Distinct is not required in your SQL ,as you are going to get only result, count(*) without group by clause returns, count of all rows within that table. Hence try this : select count(*) from table1....

https://stackoverflow.com

sql - What's the difference between select distinct count, and ...

Query select count(distinct a) will give you number of unique values in a. While query select distinct count(a) will give you list of unique counts of values in a. Without grouping it will be just on...

https://stackoverflow.com

SQL COUNT - 1Keydata SQL 語法教學

"IS NOT NULL" 是"這個欄位不是空白" 的意思。 COUNT 和DISTINCT 經常被合起來使用,目的是找出表格中有多少筆不同的資料(至於這些資料實際上是什麼並不重要)。舉例來說,如果我們要找出我們的表格中有多少個不同的Store_Name,我們就鍵入,. SELECT COUNT (DISTINCT Store_Name) FROM Stor...

https://www.1keydata.com

SQL COUNT DISTINCT 函数 - w3school 在线教程

定义和用法. 可以一同使用DISTINCT 和COUNT 关键词,来计算非重复结果的数目。 语法. SELECT COUNT(DISTINCT column(s)) FROM table. 例子. 注意:下面的例子仅适用于ORACLE 和Microsoft SQL server,不能用于Microsoft Access。 "Orders"表:. Company, OrderNu...

http://www.w3school.com.cn

SQL SELECT DISTINCT Statement - W3Schools

SELECT COUNT(DISTINCT Country) FROM Customers;. Try it Yourself ». Note: The example above will not work in Firefox and Microsoft Edge! Because COUNT(DISTINCT column_name) is not supported in Microsof...

https://www.w3schools.com

SQL SELECT DISTINCT | COUNT | ROWS | On one columns | Examples

SQL SELECT DISTINCT with COUNT on ROWS or on one columns.

http://www.dofactory.com

SQL Server query - Selecting COUNT(*) with DISTINCT - Stack Overflow

Count all the DISTINCT program names by program type and push number. SELECT COUNT(DISTINCT program_name) AS Count, program_type AS [Type] FROM cm_production WHERE push_number=@push_number GROUP BY pr...

https://stackoverflow.com