(1) If the argument is an empty sequence, fn:string(seq) will return a zero-length string, but the other function returns an empty sequence.

(2) If the specified XPath returns an empty sequence, XMLEXISTS returns false.

(3) Specifies that the expression can not be matched against an empty sequence.

(4) This is because, for a given row, the XMLEXISTS predicate evaluates to false only if the XQuery expression inside returns the empty sequence.

(5) In this case the starting value is returned for an empty sequence, and the function is first applied to the starting value and the first sequence item, then to the result and the next item, and so on.

(6) However, without the square brackets the XQuery expression is a Boolean expression which always returns a Boolean value and never the empty sequence.

(7) If the type annotation denotes a complex type with empty content(Sentencedict), then the typed value of the node is the empty sequence and its string value is the zero-length string.

(8) The glob * (star) matches any character or sequence of characters, including an empty sequence.

(9) The XMLEXISTS is a Boolean function that takes an XPath expression as input and returns FALSE if the XPath expression returns an empty sequence and TRUE otherwise.

(10) The value produced by that XQuery is either the customer's name element if the predicate is true, or the empty sequence otherwise.

(11) The right-hand side of the COPY clause must evaluate to a single node, meaning it cannot be an empty sequence or a sequence of more than one item.

(12) Specifies that the expression can not be matched against empty sequence.