[flwor表达式/数据库检索命令]
标准类型for, let, where, order by, return
1
for语句
ex:>
for $x in (1, 2, 3)
return <number>{ $x }</number>
re:>
<number>1</number>
<number>2</number>
<number>3</number>
2
let语句
ex:>
let $a := (1, 2, 3)
return <numbers>{ $a }</numbers>
re:><numbers>1 2 3</numbers>
3
where语句
ex:>
for $x in (1, 2, 3)
where $x >= 2
return <number>{ $x }</number>
re:>
<number>2</number>
<number>3</number>
4
order by 语句
ex:>
for $x in (<greeting/>, <greeting from="weiqi"/>, <greeting from="brian"/>)
order by $x/@from ascending empty least
return $x
