Teradata SQL Flashcards

Which Teradata SQL command is used to remove all rows from a table without logging individual row deletions?

Answer: DELETE ALL

DELETE ALL (or DELETE tablename ALL) removes all rows quickly; Teradata also supports TRUNCATE TABLE for similar fast deletion.

What is the purpose of the WITH clause (Common Table Expression) in Teradata SQL?

Answer: Defines a temporary named result set for use within the query

The WITH clause defines a Common Table Expression (CTE), which is a temporary named result set referenced within the same query.

Which string function in Teradata returns the position of a substring within a string?

Answer: INDEX

The INDEX function in Teradata returns the position of the first occurrence of a substring within a string.

What does COALESCE return in Teradata SQL?

Answer: The first non-NULL value from a list of expressions

COALESCE evaluates each expression in order and returns the first non-NULL value found in the list.

In Teradata, which keyword is used to sort query results in descending order?

Answer: DESC

The DESC keyword in an ORDER BY clause sorts the result set from the highest to the lowest value.

Which Teradata function formats a date value as a character string?

Answer: TO_CHAR

TO_CHAR converts a date or numeric value to a character string using a specified format mask.