SAXONICA |

The expression `for $x in E1 return E2`

returns the sequence that results from evaluating
`E2`

once for every item in the sequence `E1`

. Note that `E2`

must
use the range variable `$x`

to refer to the item being
tested; it does not become the context item. For example, ```
sum(for $v in order-item return
$v/price * $v/quantity)
```

returns the total value of (price times quantity) for all the
selected `order-item`

elements.