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DP-900 · 2 Identify considerations for relational data on Azure

SQL statement types

Exam objective: Identify common structured query language (SQL) statements

SQL statements fall into three groups, defining database objects, controlling access to them, and reading or changing the rows inside them.

SQL, or Structured Query Language, is the standard way to work with a relational database. Its statements split into three groups.

Data Definition Language, or DDL, defines the objects in a database. CREATE adds a new object such as a table, ALTER changes its structure, and DROP removes it entirely.

Data Control Language, or DCL, manages permissions. GRANT allows an action, DENY blocks it, and REVOKE takes back a permission that was granted before.

Data Manipulation Language, or DML, works with the rows inside a table. SELECT reads them, INSERT adds new ones, UPDATE changes existing ones, and DELETE removes them. SELECT, UPDATE and DELETE normally act on every row unless you narrow them with a WHERE clause:

UPDATE Product
SET Price = 12.99
WHERE ID = 7;

Leave out the WHERE clause and the statement touches every row in the table, with no confirmation prompt.

On the exam, sort a statement by what it touches: a database object means DDL, a permission means DCL, and table rows mean DML.

Key points

  • Data Definition Language (DDL) statements such as CREATE, ALTER and DROP create, change or remove database objects.
  • Data Control Language (DCL) statements such as GRANT, DENY and REVOKE manage who can access an object.
  • Data Manipulation Language (DML) statements such as SELECT, INSERT, UPDATE and DELETE read and change the rows inside a table.
  • A WHERE clause limits UPDATE, DELETE and SELECT statements to matching rows. Without one, the statement applies to every row.
  • Database vendors add their own extensions on top of standard SQL, which is why dialects such as Transact-SQL and pgSQL differ.

Exam trap

Leaving out the WHERE clause on an UPDATE or DELETE statement does not fail safely. SQL has no confirmation prompt, so the statement runs against every row in the table.

Check yourself

A database administrator wants to take back a permission that was granted to a user earlier. Which SQL statement should they use?

Practice all 8 on this topic

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Checked against Microsoft Learn on October 1, 2026.

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