MySQL subquery GROUP by usage

1 GROUP by indicates a sort, followed by the first data in each group, where the condition is indicated, if you need conditional filtering on the order, you should follow the property name with a + condition. and cannot use where

2 aggregate function sum () count () Avg () max () min () group by is a group of queries that divide the same class of criteria into a set of general group by that is used in conjunction with an aggregate function. For example

A person who has a score of more than 80 points for each course Select Name,min (Score) as a from Zt_score GROUP by ' name ' has a>80

Print out the following format

Select Date,sum (result= ' wins ') as Win,sum (result= ' negative ') as lose from Zt_miya GROUP by date

MySQL subquery GROUP by usage