case

The case command evaluates a list of conditions and returns corresponding values for the first condition that is true, similar to a SQL CASE or a switch statement.

Syntax

case(condition1, result1, condition2, result2, ..., conditionN, resultN[, defaultResult])

• condition1, condition2, ..., conditionN: Expressions that evaluate to boolean values.
• result1, result2, ..., resultN: The values to return if the corresponding condition is true.
• defaultResult: The value to return if none of the conditions are true.

Returns

The value of the first resultN where conditionN is true, or defaultResult if none match.

Examples

Example 1: Basic usage

This query creates a new column AgeGroup based on the age column. It assigns 'Minor' for ages less than 18, 'Adult' for ages between 18 and 64, and 'Senior' for all other ages.

datatable(age:int64) [
    10,
    25,
    70
]
| extend AgeGroup = case(
    age < 18, "Minor",
    age >= 18 and age < 65, "Adult",
    "Senior"
)

Output

age	AgeGroup
10	Minor
25	Adult
70	Senior

Example 2: Multiple conditions

This query assigns a letter grade in a new Grade column based on the score. 'F' is the default result for any score below 60.

datatable(score:int64) [
    95,
    85,
    75,
    65,
    55
]
| extend Grade = case(
    score >= 90, "A",
    score >= 80, "B",
    score >= 70, "C",
    score >= 60, "D",
    "F"
)

Output

score	Grade
95	A
85	B
75	C
65	D
55	F