The following table shows the result of the CAST function or Teradata conversion based on the options specified. If the target precision is higher than zero, trailing zeros are added in the result to adjust the precision.
| Option | Local Timestamp Value |
|---|---|
| AT LOCAL | Formed from source date_expression with time portion set to '00:00:00'. Result is formed from this local timestamp value adjusted to UTC by subtracting time zone displacement based on current session time zone. This is the same as not specifying the AT clause. |
| AT [ TIME ZONE ] expression | Formed from source date_expression with time portion set to '00:00:00'. Result is formed from this local timestamp value adjusted to UTC by subtracting time zone displacement defined by expression. |
| AT [ TIME ZONE ] time_zone_string | Formed from source date_expression with time portion set to '00:00:00'. Time zone displacement is based on time_zone_string and local timestamp value. Result is formed from local timestamp value adjusted to UTC by subtracting time zone displacement. |