UNWIND¶
The UNWIND statement splits a list into separated rows.
UNWIND can function as an individual statement or a clause in a statement.
Syntax¶
ngql
UNWIND <list> AS <alias> <RETURN clause>;
Split a list¶
The following example splits the list [1,2,3] into three rows.
ngql
nebula> UNWIND [1,2,3] AS n RETURN n;
+---+
| n |
+---+
| 1 |
| 2 |
| 3 |
+---+
Return a list with distinct items¶
Use WITH DISTINCT in the UNWIND statement to return a list with distinct items.
Example 1¶
The following statement:
- Splits the list
[1,1,2,2,3,3]into rows. - Removes duplicated rows.
- Sorts the rows.
- Transforms the rows to a list.
ngql
nebula> WITH [1,1,2,2,3,3] AS n \
UNWIND n AS r \
WITH DISTINCT r AS r \
ORDER BY r \
RETURN collect(r);
+------------+
| collect(r) |
+------------+
| [1, 2, 3] |
+------------+
Example 2¶
The following statement:
- Outputs the vertices on the matched path into a list.
- Splits the list into rows.
- Removes duplicated rows.
- Transforms the rows to a list.
ngql
nebula> MATCH p=(v:player{name:"Tim Duncan"})--(v2) \
WITH nodes(p) AS n \
UNWIND n AS r \
WITH DISTINCT r AS r \
RETURN collect(r);
+----------------------------------------------------------------------------------------------------------------------+
| collect(r) |
+----------------------------------------------------------------------------------------------------------------------+
| [("player100" :player{age: 42, name: "Tim Duncan"}), ("player101" :player{age: 36, name: "Tony Parker"}), |
|("team204" :team{name: "Spurs"}), ("player102" :player{age: 33, name: "LaMarcus Aldridge"}), |
|("player125" :player{age: 41, name: "Manu Ginobili"}), ("player104" :player{age: 32, name: "Marco Belinelli"}), |
|("player144" :player{age: 47, name: "Shaquile O'Neal"}), ("player105" :player{age: 31, name: "Danny Green"}), |
|("player113" :player{age: 29, name: "Dejounte Murray"}), ("player107" :player{age: 32, name: "Aron Baynes"}), |
|("player109" :player{age: 34, name: "Tiago Splitter"}), ("player108" :player{age: 36, name: "Boris Diaw"})] |
+----------------------------------------------------------------------------------------------------------------------+