Teradata SQL Flashcards

What is the role of the GROUP BY clause in a Teradata SELECT statement?

Answer: Groups rows sharing common column values for aggregate calculations

GROUP BY organizes rows that share the same values in specified columns into summary groups, enabling aggregate functions to operate on each group.

Which Teradata SQL statement is used to change an existing table's structure, such as adding a column?

Answer: ALTER TABLE

ALTER TABLE modifies an existing table's structure, allowing operations like adding, dropping, or modifying columns.

What does the BETWEEN operator do in a Teradata WHERE clause?

Answer: Tests whether a value falls within an inclusive range

BETWEEN tests whether a value is within a specified inclusive range, equivalent to value >= low AND value <= high.

In Teradata, which window function assigns a unique sequential integer to each row within a partition?

Answer: ROW_NUMBER()

ROW_NUMBER() assigns a unique consecutive integer starting at 1 to each row within a partition, with no ties.

Which Teradata SQL command permanently saves changes made during a transaction?

Answer: COMMIT

COMMIT (or ET in BTEQ) permanently writes all changes made since the last commit or start of the transaction to the database.

What is the result of a Cartesian product in Teradata when two tables are joined without a condition?

Answer: Every row in the first table is combined with every row in the second table

A Cartesian product (CROSS JOIN) combines every row from the first table with every row from the second table, producing m×n rows.