CASE

Logical functions

Syntax

Version 1:

CASE expression
    WHEN value_1 THEN result_1
    [ WHEN value_2 THEN result_2
      ... ]
    ELSE default_result
END

Version 2:

CASE(
    expression,
    value_1, result_1,
  [ value_2, result_2,
    ... ]
    default_result
)

Description

Compares expression to value_1, value_2, ... consecutively and returns the corresponding result for the first match. If no match is found, it returns default_result.

Argument types:

expression — Any
value_1 — Any
result_1 — Any
value_2 — Any
result_2 — Any
default_result — Any

Return type: Same type as (result_1, result_2, default_result)

Note

Arguments (result_1, result_2, default_result) must be of the same type.

Examples

CASE (
    [country],
    "BY", "Белоруссия",
    "KZ", "Казахстан",
    "RU", "Россия",
    "TR", "Турция",
    "UZ", "Узбекистан",
    "Другая страна"
)

CASE [country]
    WHEN "BY" THEN "Белоруссия"
    WHEN "KZ" THEN "Казахстан"
    WHEN "RU" THEN "Россия"
    WHEN "TR" THEN "Турция"
    WHEN "UZ" THEN "Узбекистан"
    ELSE "Другая страна"
END

Data source support

Materialized Dataset, ClickHouse 1.1, Microsoft SQL Server 2017 (14.0), MySQL 5.6, PostgreSQL 9.3.