17.10 - Difference Between SUBSTRING and SUBSTR - Advanced SQL Engine - Teradata Database

Teradata Vantageā„¢ - SQL Functions, Expressions, and Predicates

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
July 2021
Content Type
Programming Reference
Publication ID
B035-1145-171K
Language
English (United States)

SUBSTRING and SUBSTR perform identically except when they operate on character strings in Teradata mode where the server character set is KANJI1 and the client character set is KanjiEBCDIC.

In this case, SUBSTR interprets n1 and n2 as physical units, making the DB2-compliant SUBSTR operate on a byte-by-byte basis. Shift-Out and Shift-In bytes are significant because the result might be formatted incorrectly. For example, the result string might not contain either the opening Shift-Out character or the closing Shift-In character.

Otherwise, if string_expression is character data, then SUBSTRING expects mixed single byte and multibyte character strings and operates on logical characters that are valid for the character set of the session. In this case, n1 is a positive integer pointing to the first character of the result and n2 is in terms of logical characters.