# Comparison Functions and Operators¶

Name Description
= Assign a value
/ Division operator
== Equal operator
!= Not equal operator
< Less than operator
<= Less than or equal operator
- Minus operator
% Modulo operator
* Multiplication operator
- Change the sign of the argument
udf_is_in() Whether a value is within a set of values

Comparison operations result in a value of true and false.

• ==

Equal. String comparisons are case-sensitive. Values of different types are not equal.

``````nebula> YIELD 'A' == 'a';
==============
| ("A"=="a") |
==============
| false |
--------------

nebula> YIELD '2' == 2;
[ERROR (-8)]: A string type can not be compared with a non-string type.
``````
• >

Greater than：

``````nebula> YIELD 3 > 2;
=========
| (3>2) |
=========
| true |
---------
``````

Greater than or equal to:

``````nebula> YIELD 2 >= 2;
[ERROR (-8)]: A string type can not be compared with a non-string type.
``````
• <

Less than:

``````nebula> YIELD 2.0 < 1.9;
=========================================
| (2.000000000000000<1.900000000000000) |
=========================================
| false                                 |
-----------------------------------------
``````

Less than or equal to:

``````nebula> YIELD 0.11 <= 0.11;
========================
| (0.110000<=0.110000) |
========================
|true |
------------------------
``````
• !=

Not equal:

``````nebula> YIELD 1 != '1';
A string type can not be compared with a non-string type.
``````
• udf_is_in()

Returns true if the first value is equal to any of the values in the list, otherwise, returns false.

``````nebula> YIELD udf_is_in(1,0,1,2);
======================
| udf_is_in(1,0,1,2) |
======================
| true               |
----------------------

nebula> GO FROM 100 OVER follow WHERE udf_is_in(\$\$.player.name, "Tony Parker"); /* This example might not work because udf_is_in might be changed in the future.*/
===============
| follow._dst |
===============
| 101         |
---------------

nebula> GO FROM 100 OVER follow YIELD follow._dst AS id | GO FROM \$-.id OVER follow WHERE udf_is_in(\$-.id, 102, 102 + 1);
===============
| follow._dst |
===============
| 100         |
---------------
| 101         |
---------------
``````

Last update: April 8, 2021