查询属性对话框
In the Query Properties dialog you can set two properties of the SQL Query, i.e. whether to return distinct values, and whether to limit the result set.
明确的数值
Expands the created select statement of the SQL Query in the current column by the parameter DISTINCT. The consequence is that identical values occurring multiple times are listed only once.
限度
设置要返回的记录数上限。