15.00 - TIME-to-UDT Conversion - Teradata Database

Teradata Database SQL Functions, Operators, Expressions, and Predicates

Product
Teradata Database
Release Number
15.00
Content Type
Programming Reference
Publication ID
B035-1145-015K
Language
English (United States)
Last Update
2018-09-24

TIME-to-UDT Conversion

Purpose

Converts TIME data to UDT data.

CAST Syntax

where:

 

Syntax element …

Specifies …

time_expression

a TIME expression to be cast to a UDT.

UDT_data_definition

the UDT type, followed by any optional FORMAT, NAMED, or TITLE data attribute phrases, to which time_expression is to be converted.

ANSI Compliance

This is ANSI SQL:2011 compliant.

As an extension to ANSI, CAST permits the use of data attribute phrases such as FORMAT.

Usage Notes

Explicit TIME-to-UDT conversion using Teradata conversion syntax is not supported.

Data type conversions involving UDTs require appropriate cast definitions for the UDTs. To define a cast for a UDT, use the CREATE CAST statement. For more information on CREATE CAST, see SQL Data Definition Language.

Implicit TIME-to-UDT Conversion

Teradata Database performs implicit TIME-to-UDT conversions for the following operations:

  • UPDATE
  • INSERT
  • Passing arguments to stored procedures, external stored procedures, UDFs, and UDMs
  • Specific system operators and functions identified in other sections of this book, unless the DisableUDTImplCastForSysFuncOp field of the DBS Control Record is set to TRUE
  • Performing an implicit data type conversion requires that an appropriate cast definition (see “Usage Notes”) exists that specifies the AS ASSIGNMENT clause.

    If no TIME-to-UDT implicit cast definition exists, Teradata Database looks for a CHAR-to-UDT or VARCHAR-to-UDT implicit cast definition that can substitute for the TIME-to-UDT implicit cast definition. Substitutions are valid because Teradata Database can implicitly cast a TIME type to the character data type, and then use the implicit cast definition to cast from the character data type to the UDT. If multiple character-to-UDT implicit cast definitions exist, then Teradata Database returns an SQL error.

    Related Topics

    For details on data types and data attributes, see SQL Data Types and Literals.