Oracle SQL Cheat Sheet 2026

The 30 highest-yield Oracle SQL facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which privilege is required to create a table in another user's schema in Oracle SQL? → CREATE ANY TABLE
2. Which Oracle SQL function returns the first non-NULL value from a list of arguments? → COALESCE
3. What is the purpose of the ORDER BY clause in a SELECT statement? → Sorts the result set by one or more columns
4. Which keyword allows you to join tables using a column with the same name in both tables in Oracle SQL? → USING
5. What does the SELECT ... FOR UPDATE statement do in Oracle? → Locks the selected rows so other transactions cannot modify them until released
6. What does SELECT * FROM employees WHERE manager_id IS NULL return? → Rows where manager_id has no value stored
7. What is the purpose of the DBMS_STATS package in Oracle SQL? → Gathers optimizer statistics on tables, indexes, and columns
8. What does the ROUND function do in Oracle SQL when called as ROUND(45.678, 1)? → Returns 45.7
9. What happens if a scalar subquery returns more than one row in Oracle SQL? → Oracle raises ORA-01427 error
10. What does the CASCADE option do in DROP TABLE in Oracle SQL? → Drops the table and all dependent foreign key constraints
11. What is a synonym in Oracle SQL? → An alternate name for a database object
12. What is a self-join in Oracle SQL? → Joining a table to itself using aliases
13. A unique identifier for each row of data in a table is: → Primary key
14. Which clause is used to filter rows AFTER grouping in Oracle SQL? → HAVING
15. Which Oracle SQL function pads the left side of a string with a specified character to a given length? → LPAD
16. Which Oracle SQL function converts a string to uppercase? → UPPER
17. In Oracle SQL, what is the legacy syntax equivalent of a LEFT OUTER JOIN? → table1, table2 WHERE table1.id = table2.id(+)
18. Which Oracle SQL statement undoes all uncommitted changes made in the current transaction? → ROLLBACK
19. In Oracle SQL, which DML statement modifies existing rows in a table? → UPDATE
20. Which Oracle SQL hint forces the optimizer to use a specific index? → /*+ INDEX(table index_name) */
21. What does the LISTAGG function do in Oracle SQL? → Aggregates string values from multiple rows into a single delimited string
22. What does the INVISIBLE option do when creating an index in Oracle SQL (11g+)? → Creates the index but the optimizer ignores it by default
23. What does NOT EXISTS return if the subquery finds no matching rows in Oracle SQL? → TRUE
24. What does the CONCAT function do in Oracle SQL? → Joins two strings together
25. Which Oracle SQL UPDATE syntax uses a subquery to update multiple columns at once? → UPDATE t SET (col1,col2) = (SELECT v1,v2 FROM src WHERE ...)
26. When using explicit cursors, list the correct command sequence to process a batch of records. → OPEN, FETCH, CLOSE
27. Which Oracle SQL clause is used to specify the join condition in an ANSI-style join? → ON
28. Choose the incorrect variable declarations. → Foo_text varchar2(10) := 'hello world';
29. Which of the following statements concerning Column Alias is incorrect? → Is Oracle vendor specific
30. In the PL/SQL language, where do you declare an explicit cursor? → In the PL/SQL declaration section.