Why dialect awareness matters in SQL - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select all columns from the table named 'employees'.

SQL

SELECT [1] FROM employees;

Drag options to blanks, or click blank then click option'

A*

BALL

CCOLUMNS

DEVERY

Attempts:

3 left

💡 Hint

Common Mistakes

Using keywords like ALL or EVERY which are not valid for selecting all columns.

Writing the word COLUMNS which is not recognized in this context.

The asterisk (*) is used in SQL to select all columns from a table.

2fill in blank

medium

Complete the code to limit the number of rows returned to 5 in a MySQL query.

SQL

SELECT * FROM products [1] 5;

Drag options to blanks, or click blank then click option'

AROWNUM

BTOP

CFETCH

DLIMIT

Attempts:

3 left

💡 Hint

Common Mistakes

Using TOP which is used in SQL Server, not MySQL.

Using FETCH or ROWNUM which belong to other SQL dialects.

In MySQL, the LIMIT keyword is used to restrict the number of rows returned.

3fill in blank

hard

Fix the error in the SQL Server query to select the top 3 rows from the 'orders' table.

SQL

SELECT [1] 3 * FROM orders;

Drag options to blanks, or click blank then click option'

ALIMIT

BROWNUM

CTOP

DFETCH

Attempts:

3 left

💡 Hint

Common Mistakes

Using LIMIT which causes syntax error in SQL Server.

Using FETCH or ROWNUM which are not valid here.

SQL Server uses TOP before the number to limit rows, unlike LIMIT in MySQL.

4fill in blank

hard

Fill both blanks to write a PostgreSQL query that fetches 10 rows starting from the 5th row.

SQL

SELECT * FROM sales [1] 10 [2] 5;

Drag options to blanks, or click blank then click option'

ALIMIT

BOFFSET

CTOP

DFETCH

Attempts:

3 left

💡 Hint

Common Mistakes

Using TOP which is not supported in PostgreSQL.

Mixing FETCH with OFFSET incorrectly.

PostgreSQL uses LIMIT to specify how many rows to return and OFFSET to skip rows.

5fill in blank

hard

Fill all three blanks to write an Oracle SQL query that fetches 5 rows after skipping the first 10 rows.

SQL

SELECT * FROM employees [2] 10 ROWS [1] [3] 5 ROWS ONLY;

Drag options to blanks, or click blank then click option'

AFETCH

BOFFSET

CFIRST

DNEXT

Attempts:

3 left

💡 Hint

Common Mistakes

Using LIMIT which is not valid in Oracle.

Swapping FIRST and NEXT keywords.

Oracle uses OFFSET to skip rows and FETCH NEXT n ROWS to limit rows returned.