How to use aggregate functions in MySQL

Aggregation function

Commands: sum(), count(), avg(), max(), min()

Function: statistics, averaging Value, maximum, minimum value

Application scenarios: This type of function is very common and is mainly used for data statistics. It is also applicable in SQL optimization.

Example:

mysql> select max(id) from t_base_user;
+---------+
| max(id) |
+---------+
| 2 |
+---------+
1 row in set (0.00 sec)

Here is a little trick. If the primary key is increasing in order, when you need how many users there are, you can use max(id) instead of the count(*) function.

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