FLWOR

FLWOR expressions include at least some of those elements in roughly the order that the acronym suggests.

FLWOR ( "flower" ) is often mentioned in the context of XQuery.

Commonly abbreviated to "FLWOR" these expressions may be used for performing joins across multiple XML streams in a similar manner to SQL.

let: You assign values to variable with let, although (as you'll soon see) you won't use let as often as you use the other FLWOR clauses.

However, the return could be a much more complex expression, including element construction and FLWOR expression.

total is assigned the result of a FLWOR expression.

The "let" statement is itself composed of a FLWOR (for, let, where, order by, and return) XQuery expression.

The same query can be formulated using FLWOR expressions commonly associated with XQuery statements.

As we have seen in the previous chapters, we are selecting and filtering elements with either a Path expression or with a FLWOR expression.

In many cases, it is possible to write a query by using either a FLWOR expression or a path expression.

All FLWOR expressions start with a for or a let expression and end with a return expression.

You have now seen how to use all the parts of a FLWOR expression except for the let clause.

It uses two FLWOR (for. Return) iterations: one to retrieve tools and one to retrieve the material used.

FLWOR is an acronym for "for, let, where, order by, return. "

This article focuses on two important kinds of XQuery expressions: FLWOR expressions and path expressions.

For example, Listing 7 shows how you can move the XPath expression fragment age lt 18 into a where clause in the FLWOR expression.

These are the elements that can make up a FLWOR expression.

The following FLWOR expression will select exactly the same as the path expression above