Implicit Character-to-Period Conversion - Advanced SQL Engine - Teradata Database

A CHARACTER or VARCHAR value is implicitly cast as a Period data type for an assignment, update, insert, merge, or parameter passing operation when the target site has a Period data type and for a comparison operation if the other operand has a Period data type. If any other non-Period value is directly assigned to a Period target site, an error is reported. In the same manner, if any other non-Period value is directly compared to a Period value, an error is reported.

During implicit conversion from CHARACTER or VARCHAR to Period data type, the ANSI DateTime format string is used to interpret the beginning and ending element values in the character string, if the response mode is other than the Field mode or if the character string data is parameterized. If the response mode is Field mode and if the character string data is not parameterized, then the target period format is used to interpret the beginning and ending element values in the character string. The following table describes this in detail.

When the ANSI DateTime format string is used to interpret the beginning and ending element values in the character string, enclosing the beginning and ending values inside the apostrophes is optional. This relaxation applies even during an explicit cast.