WHERE Syntax¶

The WHERE clause allows you to specify a search condition for the data returned by a query. The following shows the syntax of the WHERE clause:

WHERE <expression> [ AND | OR <expression> ...])

Currently, the WHERE statement applies to the GO and LOOKUP statement. Note some WHERE filter conditions are not supported in the LOOKUP statement. Refer to the LOOKUP Doc for details.

Usually, WHERE is a set of logical combination that filters vertex or edge properties.

As syntactic sugar, logic AND is represented by AND or && and logic OR is represented by OR or ||.

Examples¶

-- the degree property of edge follow is greater than 90.
nebula> GO FROM 100 OVER follow WHERE follow.degree > 90;
-- the following result is returned:
===============
| follow._dst |
===============
| 101         |
---------------

-- find the destination vertex whose age is equal to the source vertex, player 104.
nebula> GO FROM 104 OVER follow WHERE $^.player.age == $$.player.age;
-- the following result is returned:
===============
| follow._dst |
===============
| 103         |
---------------

-- logical combination is allowed.
nebula> GO FROM 100 OVER follow WHERE follow.degree > 90 OR $$.player.age != 33 AND $$.player.name != "Tony Parker";
-- the following result is returned:
===============
| follow._dst |
===============
| 101         |
---------------
| 106         |
---------------

-- the condition in the WHERE clause is always TRUE.
nebula> GO FROM 101 OVER follow WHERE 1 == 1 OR TRUE;
-- the following result is returned:
===============
| follow._dst |
===============
| 100         |
---------------
| 102         |
---------------

Filtering Edge Rank with WHERE¶

You can filter the edge rank with the WHERE clause. For example:

nebula> CREATE SPACE test;
nebula> USE test;
nebula> CREATE EDGE e1(p1 int);
nebula> CREATE TAG person(p1 int);
nebula> INSERT VERTEX person(p1) VALUES 1:(1);
nebula> INSERT VERTEX person(p1) VALUES 2:(2);
nebula> INSERT EDGE e1(p1) VALUES 1->2@0:(10);
nebula> INSERT EDGE e1(p1) VALUES 1->2@1:(11);
nebula> INSERT EDGE e1(p1) VALUES 1->2@2:(12);
nebula> INSERT EDGE e1(p1) VALUES 1->2@3:(13);
nebula> INSERT EDGE e1(p1) VALUES 1->2@4:(14);
nebula> INSERT EDGE e1(p1) VALUES 1->2@5:(15);
nebula> INSERT EDGE e1(p1) VALUES 1->2@6:(16);
nebula> GO FROM 1 OVER e1 WHERE e1._rank>2 YIELD e1._src, e1._dst, e1._rank AS Rank, e1.p1 | ORDER BY Rank DESC;
====================================
| e1._src | e1._dst | Rank | e1.p1 |
====================================
| 1       | 2       | 6    | 16    |
------------------------------------
| 1       | 2       | 5    | 15    |
------------------------------------
| 1       | 2       | 4    | 14    |
------------------------------------
| 1       | 2       | 3    | 13    |
------------------------------------

Last update: April 8, 2021