Last 2 digits of ISO 8601 week-numbering year Last 3 digits of ISO 8601 week-numbering year ISO 8601 week-numbering year (4 or more digits) To construct format strings, you use the following template patterns for formatting date and time values. The timestamp is a string that represents a timestamp value in the format specified by format. The TO_TIMESTAMP() function requires two arguments: The following illustrates the syntax of TO_TIMESTAMP() function: TO_TIMESTAMP(timestamp, format) Arguments The PostgreSQL TO_TIMESTAMP() function converts a string to a timestamp according to the specified format. > Index Scan using timestamputc_time_177168 on time_177168 (cost=11.91 rows=747486 width=81) (actual time=: in this tutorial, you will learn how to use the PostgreSQL TO_TIMESTAMP() function to convert a string to a timestamp based on a specified format New Query (Based on Accepted Solution) EXPLAIN ANALYSE SELECT "Timestamp","Column1","Column2","Column3" FROM time_177168 WHERE "Timestamp">'T00:59:00-06:00' ORDER BY "TimestampUTC" limit 5000 Sort Method: top-N heapsort Memory: 1089kB Sort Key: ((Timestamp)::timestamp with time zone) Original Query: EXPLAIN ANALYSE SELECT "Timestamp","Column1","Column2","Column3" FROM time_177168 WHERE "Timestamp">'T00:59:00-06:00' ORDER BY ("Timestamp"::timestamp with time zone) limit 5000 Using the solution below I was able to get the query performance to an acceptable level. I am not able to change the data type for the existing "Timestamp" column because of legacy applications that use this database.Īny ideas or suggestion would be greatly appreciated. The overall goal is to be able to quickly order queries by UTC time. Here are a few examples of my attempts to generate the new column but they all return:ĮRROR: generation expression is not immutable SQL state: 42P17Īttempt 1: alter table public.time_177168 ADD COLUMN "TimestampUTC" timestamp with time zone GENERATED ALWAYS AS ("Timestamp"::timestamp with time zone) STOREĪttempt 2: alter table public.time_177168 ADD COLUMN "TimestampUTC" timestamp with time zone GENERATED ALWAYS AS ("Timestamp"::timestamp AT TIME ZONE 'ETC/UTC') STORED Here is a data example from the table: select "Timestamp",("Timestamp"::timestamp with time zone) from public.time_177168 limit 1 I have tried many methods suggested in forums and documentation but I have not been able to get anything to work. I want to generate a timestamptz formatted column with a continuous UTC timestamp but have been unable to do it. My table has a "Timestamp" column (text type) with YYYY-MM-DDTHH:MM:SSZ formatted dates.
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