This statement is a Teradata extension to the ANSI SQL:2011 standard.
INTERVAL-to-Fixed CHARACTER Conversion
When the target data type is CHAR(n), then n must be equal to or greater than the length of the canonical form of the value as represented by a character string literal.
If n is greater than that length, trailing pad characters are added to pad the canonical representation.
If n is too small, then a string truncation error is returned.
INTERVAL-to-VARCHAR Conversion
When the target data type is VARCHAR(n), then n must be equal to or greater than the length of the canonical form of the value as represented by a varying character string literal.
If n is too small, then a string truncation error is returned.