> ## Documentation Index
> Fetch the complete documentation index at: https://docs.honeycomb.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Conditional Functions in Calculated Fields

> Conditional functions available for calculated field formulas in Honeycomb, including IF, ELSE, and related boolean expression operators.

Conditional functions evaluate a condition that is applied to boolean expressions.

## `IF`

The `IF` statement takes two or more arguments.
Every pair of arguments is evaluated as a condition; the final argument is the default: `IF( condition, then-val [, condition2, then-val2]... [, else-val])`.

* If `condition` evaluates to true, evaluates to `then-val`.
* If `condition2` is specified, then if it is true, evaluates to `then-val2`.
* If `else-val` is not specified, evaluates to null.
* Otherwise evaluates to  `else-val`.

All non-zero numbers, as well as the string `true`, evaluate to `true`.

```ruby theme={}
# Usage: `IF( condition, then-val [, condition2, then-val2]... [, else-val])`
# Examples
IF(CONTAINS($team_name, "acme"), "important-customer", "everyone else")
IF(GTE($http_status, 400), 1, 0)
IF(GTE($duration_ms, 500), "slow")

# The multiple-value form can be used as a type of case statement,
# but SWITCH is more efficient if the same expression is being tested for strict equality.
IF(EQUALS($path,"/login"),"login",
   CONTAINS($path,"/browse/"),"browsing",
   "other"
  )
```

Note that the multi-argument `IF` is equivalent to nested `IF` statements:

```ruby theme={}
# nested IF
IF(condition, value,
  IF(condition2, value2,
    IF(condition3, value3, default)
  )
)

# equivalent with multi-condition IF
IF(condition, value,
   condition2, value2,
   condition3, value3, default)
```

## `SWITCH`

The `SWITCH` statement takes three or more arguments.
The first argument is the value to test the cases against.
Every pair of arguments is evaluated as a case and the value to return.
If there is an unpaired final argument, it will be returned as the default if none of the cases match.
If no default value exists, then null will be returned.
`SWITCH( expression, case1, val1[, case2, val2]... [, default-val])`.

* If `expression` equals `case1`, evaluates to `val1`.
* If `case2` is specified and equals `expression`, evaluates to `val2`.
* If `default-val` is not specified, evaluates to null.
* Otherwise evaluates to  `default-val`.

The rules for [`EQUALS`](/reference/calculated-field-formula/comparison/#equals) apply for testing cases.

```ruby theme={}
# Usage: `SWITCH( expression, case1, val1[, case2, val2]... [, default-val])`
# Examples
SWITCH(REG_VALUE($service.name, "^([a-z]+)-shard-"),
  "alpha", "blue-owls",
  "beta", "violet-octopi",
  "delta", "violet-octopi",
  "gamma", "orange",
  "platform"
)
```

## `COALESCE`

Evaluates to the first non-empty argument.
This is useful for similar fields where fallback values are preferable to null.

```ruby theme={}
# Usage: COALESCE(arg1, arg2, ...)
# Examples
COALESCE($full_name, $email)
COALESCE($container_id, $hostname, $availability_zone, "unknown")
COALESCE($service.name, $service_name, "unknown")

# This can be used to approximate a case statement. For some cases, this is easier to write than the multi-factor IF statement.
COALESCE(
  IF(GTE($duration_ms, 200), "slow"),
  IF(GTE($status, 500), $error_message),
  IF(CONTAINS($team, "acme"), "high priority"),
  "normal"
)
```