DATEVALUE
Returns the internal date number for text in quotes.
The internal date number is returned as a number. The number is determined by the date system that is used by Collabora Office to calculate dates.
If the text string also includes a time value, DATEVALUE only returns the integer part of the conversion.
DATEVALUE("Text")
Text is a valid date expression and must be entered with quotation marks.
=DATEVALUE("1954-07-20") yields 19925.