Which two are true about aggregate functions?()
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.
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Access2003数据库属于()数据库系统。
A. 树状
B. 逻辑型
C. 层次型
D. 关系型
地方性甲状腺肿的主要病因是()
A. 摄入过多的碘
B. 碘摄入量缺乏
C. 摄入过多的氟
D. 氟摄入量缺乏
E. 摄入过多的镉