Q: 144 Which two are true about aggregate functions? (Choose two.)A. You can use aggregate functions in any clause of a SELECT statement.
B. You can use aggregate functions only in the column list of the SELECT clause and in the WHERE clause
of a SELECT statement.
C. You can mix single row columns with aggregate functions in the column list of a SELECT statement by
grouping on the single row columns.
D. You can pass column names, expressions, constants, or functions as parameters to an aggregate function.
E. You can use aggregate functions on a table, only by grouping the whole table as one single group.
F. You cannot group the rows of a table by more than one column while using aggregate functions.
Answer: C, D我看懂了A、B、C选项内容的意思，问下DEF选项是啥意思？
B. You can use aggregate functions only in the column list of the SELECT clause and in the WHERE clause
of a SELECT statement.
C. You can mix single row columns with aggregate functions in the column list of a SELECT statement by
grouping on the single row columns.
D. You can pass column names, expressions, constants, or functions as parameters to an aggregate function.
E. You can use aggregate functions on a table, only by grouping the whole table as one single group.
F. You cannot group the rows of a table by more than one column while using aggregate functions.
Answer: C, D我看懂了A、B、C选项内容的意思，问下DEF选项是啥意思？
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E : 只有当你把整个表作为一个组的时候，聚合函数才能使用
F : 当用聚合函数的时候，你不能把一个表的2个或多个列分组（就是group by 不能有2或多个列）个人之见~~