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PHONE_VALID

Description

PHONE_VALID checks whether a string is a valid phone number using Google's libphonenumber. It performs two checks in sequence:

  1. Possible number, is the length plausible for any phone number in that country?
  2. Valid number, does the number match a known number range or pattern for that country?

A number that passes the length check but does not match a known range returns false. A number that cannot be parsed at all returns unknown.

The input string may contain spaces, dashes, or parentheses, these are handled by the parser. A leading 00 is treated as an international dialling prefix, equivalent to +.

If the number does not start with + or 00, a country_code must be provided to interpret it as a local number. Without one, the result is unknown.

Syntax

PHONE_VALID(phone, country_code?)

Returns: true if the number is valid, false if it is structurally invalid, unknown if the input cannot be parsed (e.g. empty string, unrecognised country code, no country context for a local number).

What counts as valid?

libphonenumber validates both number length and whether the number falls within a known range for the country. This means:

  • +41791234567 → true: valid Swiss mobile number
  • +41791234 → false: too short to be a valid Swiss number
  • +41999999999 → false: correct length but not a valid Swiss number range
  • 0041123 → false: the 00 prefix is treated as +, making it +41123, which is too short
  • +99999999999 → unknown: unrecognised country calling code; the parser throws a parse exception rather than returning a structural result

Examples, Switzerland (CH, +41)

PHONE_VALID('+41791234567')

Returns true, valid Swiss mobile number in international format.

PHONE_VALID('0041791234567')

Returns true, 00 is treated as +, equivalent to +41791234567.

PHONE_VALID('0791234567', 'CH')

Returns true, valid Swiss mobile number in local format.

PHONE_VALID('+41791234')

Returns false, too short to be a valid Swiss number (only 7 digits after the country code, Swiss numbers require 9).

PHONE_VALID('+41999999999')

Returns false, length is plausible, but the number does not fall within any known Swiss number range.

PHONE_VALID('079123', 'CH')

Returns false, too short.

Examples, Germany (DE, +49)

PHONE_VALID('+4915123456789')

Returns true, valid German mobile number (Telekom range).

PHONE_VALID('015123456789', 'DE')

Returns true, valid German mobile number in local format.

PHONE_VALID('+493012345678')

Returns true, valid Berlin landline.

PHONE_VALID('+491234')

Returns false, too short.

PHONE_VALID('+4919999999999')

Returns false, does not match a known German number range.

Examples, United Kingdom (GB, +44)

PHONE_VALID('+447911123456')

Returns true, valid UK mobile number.

PHONE_VALID('07911123456', 'GB')

Returns true, valid UK mobile number in local format.

PHONE_VALID('+442071234567')

Returns true, valid London landline.

PHONE_VALID('+44791112')

Returns false, too short.

PHONE_VALID('+44099999999')

Returns false, does not match a known UK number range.

Edge cases

PHONE_VALID('0791234567', 'XX')

Returns unknown, 'XX' is not a recognised country code.

PHONE_VALID('0791234567')

Returns unknown, no country context to interpret the local number.

PHONE_VALID('+99999999999')

Returns unknown, +999 is not a recognised country calling code, so the parser throws a parse exception and cannot return a structural result.

Example in context

p is Person
PHONE_VALID(p.mobile_number, 'CH')

Returns true if the entered number is a valid Swiss phone number or a valid internationally prefixed number. Commonly used to validate phone inputs before allowing case progression.