Truncates a date, time, or timestamp to the specified part. Think of this as rounding back in time. Truncating to the week would give the first date of the week. Date Part examples: Year, Month, Week, Day, Hour, Minute, Second. NOTE: The database returns Monday as the beginning of the week and Sunday as the last day in the week.

​Syntax

DATE_TRUNC(Date or Time Part,Date/Time value)

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​Arguments

Date or Time Part:

The keyword that will determine what you are trying to truncate your Date or Time field to be.

Date/Time value:

The Date or Time you want to truncate.

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​Example

DATE_TRUNC(WEEK, '2019-02-01') = 1/28/2019
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2/1/2019 is Friday
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1/28/2019 is the Monday of that week.
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DATE_TRUNC('YEAR', '2019-03-25') =2019-01-01
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DATE_TRUNC('MONTH', '2019-03-25') =2019-03-01