Categories:

Data metric functions

DUPLICATE_COUNT (system data metric function)

Returns the count of column values that have duplicates, including NULL values.

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 to automate data quality checks.

Syntax

SNOWFLAKE.CORE.DUPLICATE_COUNT(<query>)
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Arguments

query

Specifies a SQL query that projects a single column.

Allowed data types

The column projected by the query must have one of the following data types:

  • DATE

  • FLOAT

  • NUMBER

  • TIMESTAMP_LTZ

  • TIMESTAMP_NTZ

  • TIMESTAMP_TZ

  • VARCHAR

Returns

The function returns a scalar value with a NUMBER data type.

Access control requirements

Associating and running a system DMF requires the USAGE privilege on the system DMF. You can grant the SNOWFLAKE.DATA_METRIC_USER database role to give users the USAGE privilege on all system DMFs. For more information, see Grant the USAGE privilege on system DMFs.

For instructions on creating a custom role with a specified set of privileges, see Creating custom roles.

For general information about roles and privilege grants for performing SQL actions on securable objects, see Overview of Access Control.

Example

Determine the number of duplicate US Social Security numbers in the SSN column:

SELECT SNOWFLAKE.CORE.DUPLICATE_COUNT(
  SELECT
    ssn
  FROM hr.tables.empl_info
);
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+---------------------------------------------------------------------+
| SNOWFLAKE.CORE.DUPLICATE_COUNT(SELECT ssn FROM hr.tables.empl_info) |
+---------------------------------------------------------------------+
| 0                                                                   |
+---------------------------------------------------------------------+
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