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Data metric functions

INVALID_UK_POSTAL_CODE_PERCENT (system data metric function)

Returns the percentage of column values that are not a UK postcode in the outward and inward form. The percentage is computed over the total row count, including NULL values in the denominator.

This topic provides the syntax for calling the function directly. To learn how to associate the function with a table or view so it runs at regular intervals, see Associate a DMF.

Syntax

SNOWFLAKE.CORE.INVALID_UK_POSTAL_CODE_PERCENT(<query>)

Arguments

query

Specifies a SQL query that projects a single column.

Allowed data types

The column projected by the query must have the VARCHAR data type.

Returns

The function returns a FLOAT value. The function returns NULL if the table or view has no rows.

Usage notes

  • The value must be an outward code (A9, A99, AA9, AA99, A9A, or AA9A), an optional single space, and an inward code (a digit and two letters).
  • The first letter cannot be Q, V, or X, and the second letter cannot be I, J, or Z. The third letter of an A9A outward code is one of A to H, J, K, P, S, T, U, or W. The fourth letter of an AA9A outward code is one of A, B, E, H, M, N, P, R, V, W, X, or Y. The two letters of the inward code cannot be C, I, K, M, O, or V.
  • The special postcodes GIR 0AA and XM4 5HQ are valid.
  • Letters are matched case-insensitively.
  • The whole value must match. A value with leading or trailing whitespace, or with separators other than the ones described here, is counted.
  • The function checks the format only; it does not verify that the postcode is assigned.

Example

Measure the percentage of invalid UK postcodes in the postcode column:

SELECT SNOWFLAKE.CORE.INVALID_UK_POSTAL_CODE_PERCENT(
  SELECT
    postcode
  FROM crm.tables.addresses
);