ClickHouse/docs/en/sql-reference/functions/comparison-functions.md

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toc_priority: 36
toc_title: Comparison
---

# Comparison Functions {#comparison-functions}

Comparison functions always return 0 or 1 (Uint8).

The following types can be compared:

-   numbers
-   strings and fixed strings
-   dates
-   dates with times

within each group, but not between different groups.

For example, you can’t compare a date with a string. You have to use a function to convert the string to a date, or vice versa.

Strings are compared by bytes. A shorter string is smaller than all strings that start with it and that contain at least one more character.

## equals, a = b and a == b operator {#function-equals}

## notEquals, a != b and a \<\> b operator {#function-notequals}

## less, \< operator {#function-less}

## greater, \> operator {#function-greater}

## lessOrEquals, \<= operator {#function-lessorequals}

## greaterOrEquals, \>= operator {#function-greaterorequals}