Select List - Teradata Database - Teradata Vantage NewSQL Engine

SQL Data Manipulation Language

Product
Teradata Database
Teradata Vantage NewSQL Engine
Release Number
16.20
Published
March 2019
Language
English (United States)
Last Update
2019-05-03
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B035-1146
lifecycle
previous
Product Category
Teradata Vantage™
*
All columns of all tables referenced in the FROM clause be returned.
When qualified by table_name, specifies that all columns of table_name only are to be returned.
View columns are explicitly enumerated when views are defined. If a table is changed after a view is defined, those changes will not appear if you perform a SELECT * query.
SELECT * …  is a column operation, projecting all the columns of a table. SELECT COUNT(*)… is a row operation, restricting and counting all the rows of a table, then reporting the cardinality of the table in question. The function of the asterisk differs in the two cases.
Since these derived columns are not actual columns of a table, you must explicitly specify PARTITION or PARTITION#L n, where n ranges from 1 to 62, inclusive, to project the PARTITION or PARTITION#L n columns for the table.
expression
SQL expression, including scalar subqueries and scalar UDFs.
If you specify a scalar UDF, it must return a value expression.
You can specify an expression that returns a UDT in a column list only if its transform group has a fromsql routine. The system automatically converts the expression from its UDT value to the external type via the fromsql routine before returning it to a client application. See Specifying UDTs in an SQL Request.
AS
Optional introduction to derived_column_name.
expression_alias_name
An alias for the column expression that is derived from expression. You must specify a derived_column_name for self-join operations.
table_name
Name of a table, queue table, derived table, or view.
table_name.* in the select list can define the table from which rows are to be returned when two or more tables are referenced in the FROM clause.