Mapping subquery and aggregate functions

映射子查询和聚合功能

You can use custom expressions in place of aggregate functions anywhere in an aggregate query.

您可以使用自订运算式取代汇总查询中任何位置的汇总函式。

Aggregate functions are used to summarize all the data in a table.

聚合函数用于汇总表中的所有数据.

They differ from aggregate functions in that they return multiple rows for each group.

与集合函数不同,他们返回各分组的多行记录.

You can combine aggregate functions with other expressions to calculate other summary values.

可将聚合函数同其他表达式组合使用,以计算其他汇总值.