选择语句

• In the example , this is represented by the outermost select statement , which uses s1 as a subquery
  在这个示例中，这由最外层的选择语句表示，这个语句将s1用作子查询。
• The second sql select creates rows for the " has name " predicate , which connects person instances to their name strings
  第二个sql选择语句为“ has _ name ”谓词创建行，它将人实例与他们的名字字符串联系起来。
• Select statements may lock database resources unnecessarily , and in some scenarios it may be necessary to use transactions for selects
  选择语句可能会对数据库资源进行不必要的锁定，在某些方案中，可能需要使用事务进行选择。
• Because both of these views are defined with a single sql select statement on the underlying table , the query performance will not suffer
  因为这两个视图都是在下面的表格上使用单独的sql选择语句进行定义，所以不会影响查询性能。
• A separate select statement will be needed to properly calculate each set of measures that share the same number and dimensional order of aggregations
  对于每一组具有相同数量和维次序的聚合的度量，需要用单独的选择语句来正确地计算。
• This outer select statement applies avg to the avg inventory column of s1 and also does the appropriate grouping on the attributes of the time dimension
  这个外层选择语句将avg ( )应用于s1的avg _ inventory列，并在time维的属性上执行适当的分组。
• There are several methods to selectively evaluate expressions in rebol . these methods provide a way for evaluation to branch many different ways , based on a key value
  这里介绍几种rebol中的选择语句，这些方法提供了一个按照关键值运行多种分支的方法。
• If the measure had a third aggregation , then the select statement generated here would itself be used as a subselect on which the third aggregation function would be applied
  ）如果这个度量还有第三个聚合，那么这个选择语句本身作为子查询，第三个聚合函数应用于它。
• The following code is the select statement constructed for our new view , using the discussion dav that we created in step 1 , based on the table of fields shown previously
  下面的代码是用于构建新视图的选择语句，代码中使用了在第一步中创建的discussion _ dav ，并基于前面显示的字段表。