and
any
as
asc
avg
boolean
by
class
concat
count
date
desc
else
exists
extends
false
float
forall
forex
from
if
implies
import
in
instanceof
int
max
min
module
newtype
none
not
or
order
predicate
rank
result
select
strictconcat
strictcount
strictsum
string
sum
super
then
this
true
unique
where
运算符
<
<=
=
>
>=
_
-
,
;
!=
/
.
..
(
)
[
]
{
}
*
%
+
|
谓词
谓词用于描述组成QL程序的逻辑关系。严格来说，谓词用于计算一组元组，看下面的例子：
predicate isCountry(string country) {
country = "Germany"
or
country = "Belgium"
or
country = "France"
}
predicate hasCapital(string country, string capital) {
country = "Belgium" and capital = "Brussels"
or
country = "Germany" and capital = "Berlin"
or
country = "France" and capital = "Paris"
}