Teradata For Beginner 5

Question 1

What is data skew in Teradata and why is it a problem?

Accepted Answer

When rows are unevenly distributed across AMPs, causing some AMPs to do much more work

Answer

Skew occurs when one or more AMPs hold significantly more rows than others, creating a bottleneck because overall query time is limited by the slowest AMP.

Question 2

Which Teradata SQL window function assigns a unique sequential number to each row within a partition?

Accepted Answer

ROW_NUMBER()

Answer

ROW_NUMBER() assigns a unique integer to every row in a partition with no gaps or ties, unlike RANK() which can have gaps.

Question 3

What is a Global Temporary Table (GTT) in Teradata?

Accepted Answer

A table whose definition persists but whose data is private and session-scoped

Answer

A GTT has a permanent definition in the data dictionary, but each session gets its own private data instance that disappears when the session ends.

Question 4

Which Teradata utility allows you to both insert new rows and update existing rows in a single operation?

Accepted Answer

MultiLoad

Answer

MultiLoad supports multiple DML operations including INSERT, UPDATE, DELETE, and UPSERT against populated tables in a single load job.

Question 5

What is the purpose of a Derived Table in a Teradata SQL query?

Accepted Answer

A temporary result set defined in a subquery within the FROM clause

Answer

A derived table is an inline view — a subquery in the FROM clause that produces a temporary result set used by the outer query.

Teradata Practice Test

Teradata Practice Test

Teradata For Beginner 5