需要帮助sql查询，分组和union / join？

Question

I have a mysql table with 3 columns:

• id [int]
• name [varchar]
• time [timestamp CURRENT_TIMESTAMP]
• flag [boolean]

I am using a query like this to group the results by day:

SELECT COUNT(DISTINCT name), DATE(time) as day FROM `table` GROUP BY day

That works fine, but what I really want to get COUNT(DISTINCT name) WHERE FLAG = 0 and COUNT(DISTINCT name) WHERE FLAG = 1 in the same query and group them by day.

How can I do that?

Answer 1

Then you have to apply grouping first on flag then on day

SELECT COUNT(DISTINCT name), DATE(time) as day FROM `table` GROUP BY flag,day