XQuery
Priscilla Walmsley (pwalmsley@datypic.com)
ISBN: 0596006349
1st edition, , O'Reilly Media, Inc.
Chapter 16: Working with numbers
Table 16-1. The number function
| Example | Return value |
|---|---|
number(doc("prices.xml")//prod[1]/price)
|
29.99
|
number(doc("prices.xml")//prod[1]/price/@currency)
|
NaN
|
number("29.99")
|
29.99
|
number(())
| NaN |
Table 16-2. Comparing numeric values
| Example | Value |
|---|---|
doc("prices.xml")//prod[3]/discount > 10
|
false
|
doc("prices.xml")//prod[3]/discount gt 10
|
Type error
|
doc("prices.xml")//prod[3]/discount > doc("prices.xml")//prod[1]/discount
| true (it is comparing the string 3.99 to the string 10.00) |
doc("prices.xml")//prod[3]/number(discount) > doc("prices.xml")//prod[1]/number(discount)
| false (it is comparing the number 3.99 to the number 10.00) |
3 gt 2
|
true
|
1 = 1.0
|
true
|
xs:float("NaN") = xs:float("NaN")
|
false
|
xs:string(xs:float("NaN")) = "NaN"
|
true
|
This table assumes that prices.xml is untyped, i.e., has not been validated with a schema. | |
Table 16-3. Examples of arithmetic expressions
| Example | Value | Value type |
|---|---|---|
5 + 3
|
8
|
xs:integer
|
5 + 3.0
|
8
|
xs:decimal
|
5 + 3.0E0
|
8
|
xs:double
|
5 * 3
|
15
|
xs:integer
|
2 + 3 * 5
|
17
|
xs:integer
|
(2 + 3) * 5
|
25
|
xs:integer
|
-3 + 5
|
2
|
xs:integer
|
() + 3
|
()
|
N/A
|
doc("prices.xml")//prod[1]/price+5
|
34.99
|
xs:decimal
|
doc("prices.xml")//prod[1]/price-5
|
()
|
N/A
|
doc("prices.xml")//prod[1]/price - 5
|
24.99
|
xs:decimal
|
Table 16-4. Examples of the
div and idiv operators| Example | Value | Value type |
|---|---|---|
14 div 4
|
3.5
|
xs:double
|
14 idiv 4
|
3
|
xs:integer
|
-14 idiv 4
|
-3
|
xs:integer
|
14.0 div 3.5
|
4.0
|
xs:decimal
|
14.0 idiv 3.5
|
4
|
xs:integer
|
() div 3
|
()
|
N/A
|
14 div 0
| Error (division by zero) |
N/A
|
xs:float("14") div 0
|
INF
|
xs:float
|
xs:double("INF") div 2
|
INF
|
xs:double
|
xs:float("NaN") div 2
|
NaN
|
xs:float
|
Table 16-5. Examples of the
mod operator| Example | Value | Value type |
|---|---|---|
14 mod 4
|
2
|
xs:integer
|
-14 mod 4
|
-2
|
xs:integer
|
14 mod -4
|
2
|
xs:integer
|
14.9 mod 2.1
|
0.2
|
xs:decimal
|
14.5E1 mod 2E1
|
5
|
xs:double
|
xs:float("14") mod 0
|
NaN
|
xs:float
|
xs:double("INF") mod 2
|
NaN
|
xs:double
|
14 mod ()
|
()
|
N/A
|
14 mod xs:double("INF")
|
14
|
xs:double
|
