postgresql distinct count
You can use this: SELECT COUNT(*) FROM (SELECT DISTINCT column_name FROM table_name) AS temp;. This is much faster than: COUNT(DISTINCT ... ,select to_char(transaction_date, 'YYYY-MM') as yyyymm ,brand ,count (distinct unique_mem_id) as count_distinct_unique_mem_id from source.table group by ...
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 postgresql distinct count 相關參考資料
PostgreSQL COUNT Function: Counting Rows That Satisfy a Condition
http://www.postgresqltutorial. postgresql COUNT(DISTINCT ...) very slow - Stack Overflow
You can use this: SELECT COUNT(*) FROM (SELECT DISTINCT column_name FROM table_name) AS temp;. This is much faster than: COUNT(DISTINCT ... https://stackoverflow.com Count Distinct with PostgreSQL - Stack Overflow
select to_char(transaction_date, 'YYYY-MM') as yyyymm ,brand ,count (distinct unique_mem_id) as count_distinct_unique_mem_id from source.table group by ... https://stackoverflow.com Select distinct values with count in PostgreSQL - Stack Overflow
Assuming the only reason for a new row is a unique city select country, count(country) AS City_Count from table group by country. https://stackoverflow.com How does COUNT(DISTINCT) work in postgreSQL - Stack Overflow
Postgres can do a lousy job with count(distinct) . Often, this works better: SELECT c2, COUNT(c1_new) FROM (SELECT c2, (CASE WHEN c1 ... https://stackoverflow.com Returning the number of distinct count in multiple columns in ...
What you want to do requires some work, because the contents of each row are independent. In Postgres, you can do this with a full outer join and row_number() ... https://stackoverflow.com PostgreSQL SELECT DISTINCT By Practical Examples
This tutorial shows you how to use the PostgreSQL SELECT DISTINCT clause to remove duplicate rows from a result set returned by a query. http://www.postgresqltutorial. sql - How to count unique values? - Server Fault
SELECT COUNT(DISTINCT ip_address) FROM bandits ... .com/questions/11250253/postgresql-countdistinct-very-slow, it could be much faster ... https://serverfault.com [MySQLPostgreSQL] 如何利用DISTINCTGROUP BY 解決重複資料，並 ...
在資料庫篩選資料時候，常常會遇到重複資料的問題，因此，我們會使用「DISTINCT」及「GROUP BY」這二個SQL語法來過濾重複資料，但若只針對某 ... https://www.jinnsblog.com PostgreSQL: SELECT COUNT(DISTINCT)
Hello! I am trying to execute query: SELECT city_id, COUNT(DISTINCT pos_id) ... GROUP BY city_id ;. but got the error: ERROR: parser: parse error at or near ... https://www.postgresql.org |