prev function for MATCH_RECOGNIZE

Applies to: check marked yes Databricks SQL check marked yes Databricks Runtime 19.0 and above

Important

This feature is in Beta. Workspace admins can control access to this feature from the Previews page. See Manage Azure Databricks previews.

Returns a preceding column value relative to the current row in the match. Use this function only in the MEASURES and DEFINE clauses of MATCH_RECOGNIZE.

Syntax

prev ( { colName | rowPatternVar.colName } [, offset ] )

Arguments

  • colName: A column from the table_reference that MATCH_RECOGNIZE operates on.
  • rowPatternVar.colName: A column qualified by a row pattern variable name. Reads the column value from rows mapped to that variable in the current match.
  • offset: An optional integral literal greater than or equal to 0. The offset relative to the current row. The default is 1.

Returns

A value of the type of colName. If the identified row is outside the current partition, returns NULL.

Common error conditions

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