Can I use… last_value(…, 'ignore nulls')


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The last_value(…) window function with the 'ignore nulls' string argument is not standard SQL. It evaluates its argument in the rows defined by the over clause in reverse order and returns the first non-null value (if any).

SELECT LAST_VALUE(<expr>, 'IGNORE NULLS') OVER (ORDER BY …)
  FROM …

Default Framing Applies

If there is no explicit framing clause the following default applies:

RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW

That means, the last_value() function cannot see beyond the ties to the current row. Open the frame to bring the last row into reach:

ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING

Normative References

'Ignore nulls' as second argument to last_value() is not covered in the international SQL standard ISO/IEC 9075:2016-2. In standard SQL the ignore nulls clause follows the parentheses as bare keywords: last_value() ignore nulls.

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