mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-17 05:03:20 +00:00
34 lines
1.2 KiB
Markdown
34 lines
1.2 KiB
Markdown
# 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.
|
|
|
|
Note. Up until version 1.1.54134, signed and unsigned numbers were compared the same way as in C++. In other words, you could get an incorrect result in cases like SELECT 9223372036854775807 > -1. This behavior changed in version 1.1.54134 and is now mathematically correct.
|
|
|
|
## equals, a = b and a == b operator {#function-equals}
|
|
|
|
## notEquals, a ! operator= b and a `<>` b {#function-notequals}
|
|
|
|
## less, `< operator` {#function-less}
|
|
|
|
## greater, `> operator` {#function-greater}
|
|
|
|
## lessOrEquals, `<= operator` {#function-lessorequals}
|
|
|
|
## greaterOrEquals, `>= operator` {#function-greaterorequals}
|
|
|
|
|
|
[Original article](https://clickhouse.yandex/docs/en/query_language/functions/comparison_functions/) <!--hide-->
|