Union, intersection, difference in DBMS Theory - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the SQL query to find all unique records from two tables using union.

DBMS Theory

SELECT * FROM table1 [1] SELECT * FROM table2;

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

AJOIN

BUNION

CINTERSECT

DEXCEPT

Attempts:

3 left

💡 Hint

Common Mistakes

Using INTERSECT instead of UNION

Using JOIN which combines columns, not rows

The UNION operator combines results from two queries and removes duplicates.

2fill in blank

medium

Complete the SQL query to find common records between two tables.

DBMS Theory

SELECT * FROM table1 [1] SELECT * FROM table2;

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

AINTERSECT

BUNION

CEXCEPT

DJOIN

Attempts:

3 left

💡 Hint

Common Mistakes

Using UNION which returns all unique rows

Using EXCEPT which returns differences

The INTERSECT operator returns only the records that appear in both tables.

3fill in blank

hard

Fix the error in the SQL query to find records in table1 but not in table2.

DBMS Theory

SELECT * FROM table1 [1] SELECT * FROM table2;

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

AEXCEPT

BINTERSECT

CUNION

DJOIN

Attempts:

3 left

💡 Hint

Common Mistakes

Using INTERSECT which returns common records

Using UNION which returns all unique records

The EXCEPT operator returns records from the first query that are not in the second query.

4fill in blank

hard

Fill both blanks to create a query that finds records in table1 but not in table2, and removes duplicates.

DBMS Theory

SELECT [1] * FROM table1 [2] SELECT * FROM table2;

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

AEXCEPT

BUNION

CDISTINCT

DINTERSECT

Attempts:

3 left

💡 Hint

Common Mistakes

Using UNION instead of EXCEPT

Not removing duplicates with DISTINCT

Use EXCEPT to find records in table1 not in table2, and DISTINCT to remove duplicates.

5fill in blank

hard

Fill all three blanks to create a query that finds records common to both tables and orders them by id.

DBMS Theory

SELECT * FROM table1 [1] SELECT * FROM table2 ORDER BY [2] [3];

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

AINTERSECT

Bid

CASC

DDESC

Attempts:

3 left

💡 Hint

Common Mistakes

Using UNION instead of INTERSECT

Ordering by wrong column or direction

INTERSECT finds common records, and ORDER BY id ASC sorts results by id in ascending order.