A.i d()

xi

An expression; use ~ to represent x if the latter is omitted

n

The number of to-be-retrieved distinct values counting from the beginning; return all values if it is absent

@o

Without sorting, remove the neighboring duplicate members only

@u

Do not sort the result set by x; it doesn’t work with @o

@h

Used over a grouped table with each group ordered to speed up grouping

@0

Discard members on which expression x is computed and gets empty result

@m

Enable parallel processing to increase performance of complex computations on a large volume of data, with indefinite computing order; the parameter and @o option are mutually-exclusive

@n

Judge whether a member is distinct or not according to position when there is only one xi and xi is a natural number

@b

Judge whether a member is distinct or not according to the bit length in a byte in order to reduce storage usage when there is only one xi and xi is a natural number

A

1

=demo.query("select * from EMPLOYEE")

2

=A1.id(DEPT)

Sort members in ascending order.

3

=A1.id@o(DEPT)

No sorting.

4

=A1.id([DEPT,GENDER])

Get the distinct values after sorting by DEPT & GENDER.

5

=["a","b","c","a"].id()

Omitting x indicates it is the sequence members themselves that will be computed to get the distinct values. Return ["a","b","c"] as with this case.

6

=A1.id@u([DEPT,GENDER])

Do not sort the result set by x.

7

=A1.id(DEPT,GENDER)

Return all distinct values as parameter n is absent.

8

=A1.id(DEPT,GENDER;4)

Return the first 4 distinct values; return all GENDER values as the field has less than 4 distinct values.

9

=file("D:/emp10.txt").import@t()

For data file emp10.txt, every 10 records are ordered by DEPT.

10

=A9.id@h(DEPT)

As A19 is grouped and ordered by DEPT, @h option is used to speed up grouping.

A

1

=demo.query("select * from DEPT")

2

=A1.id(FATHER)

Return value: [null,1,2,11,12].

3

=A1.id@0(FATHER)

Return value: [1,2,11,12] .