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

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slug: /en/sql-reference/functions/comparison-functions
sidebar_position: 35
sidebar_label: Comparison
---

# Comparison Functions

Below comparison functions return 0 or 1 as Uint8.

The following types can be compared:
- numbers
- strings and fixed strings
- dates
- dates with times

Only values within the same group can be compared (e.g. UInt16 and UInt64) but not across groups (e.g. UInt16 and DateTime).

Strings are compared byte-by-byte. Note that this may lead to unexpected results if one of the strings contains UTF-8 encoded multi-byte characters.

A string S1 which has another string S2 as prefix is considered longer than S2.

## equals, `=`, `==` operators

**Syntax**

```sql
equals(a, b)
```

Alias:
- `a = b` (operator)
- `a == b` (operator)

## notEquals, `!=`, `<>` operators

**Syntax**

```sql
notEquals(a, b)
```

Alias:
- `a != b` (operator)
- `a <> b` (operator)

## less, `<` operator

**Syntax**

```sql
less(a, b)
```

Alias:
- `a < b` (operator)

## greater, `>` operator

**Syntax**

```sql
greater(a, b)
```

Alias:
- `a > b` (operator)

## lessOrEquals, `<=` operator

**Syntax**

```sql
lessOrEquals(a, b)
```

Alias:
- `a <= b` (operator)

## greaterOrEquals, `>=` operator

**Syntax**

```sql
greaterOrEquals(a, b)
```

Alias:
- `a >= b` (operator)