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Data metric functions

INVALID_NL_BSN_PERCENT (system data metric function)

Returns the percentage of column values that are not a Dutch citizen service number (BSN) of eight or nine digits. 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_NL_BSN_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 eight or nine digits, without spaces or other separators. The eight-digit form is the nine-digit number with its leading zero omitted.
  • 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 apply the eleven-test (elfproef) or verify that the number was issued.

Example

Measure the percentage of invalid Dutch citizen service numbers in the bsn column:

SELECT SNOWFLAKE.CORE.INVALID_NL_BSN_PERCENT(
  SELECT
    bsn
  FROM hr.tables.employees
);