mirror of https://gitee.com/bigwinds/arangodb
52 lines
1.7 KiB
Markdown
52 lines
1.7 KiB
Markdown
LIMIT
|
|
=====
|
|
|
|
The *LIMIT* statement allows slicing the result array using an
|
|
offset and a count. It reduces the number of elements in the result to at most
|
|
the specified number. Two general forms of *LIMIT* are followed:
|
|
|
|
```js
|
|
LIMIT count
|
|
LIMIT offset, count
|
|
```
|
|
|
|
The first form allows specifying only the *count* value whereas the second form
|
|
allows specifying both *offset* and *count*. The first form is identical using
|
|
the second form with an *offset* value of *0*.
|
|
|
|
```js
|
|
FOR u IN users
|
|
LIMIT 5
|
|
RETURN u
|
|
```
|
|
|
|
Above query returns the first five documents of the *users* collection.
|
|
It could also be written as `LIMIT 0, 5` for the same result.
|
|
Which documents it actually returns is rather arbitrary, because no explicit
|
|
sorting order is specified however. Therefore, a limit should be usually
|
|
accompanied by a `SORT` operation.
|
|
|
|
The *offset* value specifies how many elements from the result shall be
|
|
skipped. It must be 0 or greater. The *count* value specifies how many
|
|
elements should be at most included in the result.
|
|
|
|
```js
|
|
FOR u IN users
|
|
SORT u.firstName, u.lastName, u.id DESC
|
|
LIMIT 2, 5
|
|
RETURN u
|
|
```
|
|
|
|
In above example, the documents of *users* are sorted, the first two results
|
|
get skipped and it returns the next five user documents.
|
|
|
|
Note that variables and expressions can not be used for *offset* and *count*.
|
|
Their values must be known at query compile time, which means that you can
|
|
use number literals and bind parameters only.
|
|
|
|
Where a *LIMIT* is used in relation to other operations in a query has meaning.
|
|
*LIMIT* operations before *FILTER*s in particular can change the result
|
|
significantly, because the operations are executed in the order in which they
|
|
are written in the query. See [FILTER](Filter.md#order-of-operations) for a
|
|
detailed example.
|
|
|