BLOB and binary types in MySQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a table with a BLOB column named 'image_data'.

MySQL

CREATE TABLE photos (id INT PRIMARY KEY, image_data [1]);

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

ABLOB

BTEXT

CVARCHAR(255)

DINT

Attempts:

3 left

💡 Hint

Common Mistakes

Using VARCHAR or TEXT for binary data causes data corruption.

Using INT for storing image data is incorrect.

The BLOB type is used to store binary large objects such as images.

2fill in blank

medium

Complete the code to insert binary data into the 'image_data' column using a placeholder.

MySQL

INSERT INTO photos (id, image_data) VALUES (1, [1]);

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

ANULL

BLOAD_FILE('path/to/image.jpg')

CNOW()

D'binarydata'

Attempts:

3 left

💡 Hint

Common Mistakes

Using string literals instead of LOAD_FILE() for binary data.

Using NOW() which returns a datetime, not binary data.

The LOAD_FILE() function reads a file and returns its contents as binary data for insertion.

3fill in blank

hard

Fix the error in the query to select the length of binary data stored in 'image_data'.

MySQL

SELECT [1](image_data) FROM photos WHERE id = 1;

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

ALENGTH

BMAX

CSUM

DCOUNT

Attempts:

3 left

💡 Hint

Common Mistakes

Using COUNT() which counts rows, not data length.

Using SUM() or MAX() which are aggregate functions not suitable here.

The LENGTH() function returns the number of bytes in the binary data.

4fill in blank

hard

Fill both blanks to create a table with a fixed-length binary column and insert data into it.

MySQL

CREATE TABLE files (id INT, data [1](16));
INSERT INTO files (id, data) VALUES (1, [2]'abc');

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

ABINARY

BVARBINARY

CTEXT

DCHAR

Attempts:

3 left

💡 Hint

Common Mistakes

Using TEXT or CHAR for binary data causes errors.

Mixing BINARY and VARBINARY incorrectly.

BINARY(16) creates a fixed-length binary column. BINARY is used to insert binary data.

5fill in blank

hard

Fill all three blanks to select binary data, convert it to hexadecimal, and alias the output.

MySQL

SELECT [1](data) AS [2] FROM files WHERE id = [3];

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

AHEX

Bbinary_hex

C1

DLENGTH

Attempts:

3 left

💡 Hint

Common Mistakes

Using LENGTH() instead of HEX() for conversion.

Not aliasing the output or using wrong alias.

Using wrong id value in WHERE clause.

HEX() converts binary data to hexadecimal string. The alias binary_hex names the output column. The WHERE clause filters by id = 1.

Practice

1. Which MySQL data type is best suited for storing large binary files like images or videos?

easy

A. BLOB

B. VARCHAR

C. TEXT

D. INT

Solution

1. Step 1: Understand data types for binary storage

   BLOB is designed to store large binary data such as images or videos.

2. Step 2: Compare with other types

   VARCHAR and TEXT store text data, INT stores numbers, so they are not suitable for binary files.

3. Final Answer:

   BLOB -> Option A

4. Quick Check:

   Large binary data = BLOB [OK]

Hint: Large binary data? Choose BLOB type [OK]

Common Mistakes:

• Choosing VARCHAR or TEXT for binary data
• Using INT for storing files
• Confusing BLOB with text types

2. Which of the following is the correct way to declare a fixed-length binary column of 16 bytes in MySQL?

easy

A. BLOB(16)

B. VARBINARY(16)

C. BINARY(16)

D. TEXT(16)

Solution

1. Step 1: Identify fixed-length binary type

   BINARY(n) stores fixed-length binary data of n bytes.

2. Step 2: Check other options

   VARBINARY is variable-length, BLOB and TEXT are for large data, not fixed-length binary.

3. Final Answer:

   BINARY(16) -> Option C

4. Quick Check:

   Fixed-length binary = BINARY(n) [OK]

Hint: Fixed-length binary? Use BINARY(size) [OK]

Common Mistakes:

• Using VARBINARY for fixed-length data
• Trying to specify size with BLOB or TEXT
• Confusing TEXT with binary types

3. Given the table files(id INT, data BLOB), what will the following query return?

SELECT LENGTH(data) FROM files WHERE id = 1;

medium

A. The first byte of the 'data' column

B. The size in bytes of the binary data stored in 'data' for id 1

C. The number of characters in the 'data' column as text

D. An error because LENGTH() does not work on BLOB

Solution

1. Step 1: Understand LENGTH() on BLOB

   LENGTH() returns the number of bytes in the binary data stored in a BLOB column.

2. Step 2: Analyze the query

   The query selects LENGTH(data) for the row where id = 1, so it returns the size in bytes of that binary data.

3. Final Answer:

   The size in bytes of the binary data stored in 'data' for id 1 -> Option B

4. Quick Check:

   LENGTH(BLOB) = byte size [OK]

Hint: LENGTH() on BLOB returns byte size [OK]

Common Mistakes:

• Thinking LENGTH() counts characters in binary
• Expecting an error from LENGTH() on BLOB
• Confusing LENGTH() with SUBSTRING()

4. You wrote this table definition:

CREATE TABLE images (id INT, img BINARY(255));

But when inserting images larger than 100 bytes, data gets truncated. What is the problem?

medium

A. BINARY cannot store binary data, use TEXT instead

B. The id column should be AUTO_INCREMENT

C. You must use VARCHAR for binary data

D. BINARY(255) is fixed-length and pads or truncates data to 255 bytes

Solution

1. Step 1: Understand BINARY(n) behavior

   BINARY(n) stores fixed-length binary data of exactly n bytes, padding or truncating as needed.

2. Step 2: Identify truncation cause

   If inserted data is larger than 255 bytes, it will be truncated to fit fixed length.

3. Final Answer:

   BINARY(255) is fixed-length and pads or truncates data to 255 bytes -> Option D

4. Quick Check:

   Fixed-length truncates data > size [OK]

Hint: Fixed-length binary truncates data exceeding size [OK]

Common Mistakes:

• Thinking BINARY can store variable-length data
• Using VARCHAR for binary data
• Ignoring fixed-length padding/truncation

5. You want to store user profile pictures in a MySQL table with columns id INT and picture. You expect pictures up to 2MB. Which data type should you choose for picture and why?

hard

A. MEDIUMBLOB, because it supports up to 16MB of binary data

B. BINARY(2000000), because fixed-length is faster

C. VARCHAR(2000000), because it stores variable-length data

D. TEXT, because pictures are text data

Solution

1. Step 1: Check size requirements

   Pictures up to 2MB require a BLOB type that can hold at least 2 million bytes.

2. Step 2: Choose suitable BLOB type

   MEDIUMBLOB supports up to 16MB, enough for 2MB pictures. BINARY(2000000) is fixed-length and too large, VARCHAR and TEXT are for text, not binary.

3. Final Answer:

   MEDIUMBLOB, because it supports up to 16MB of binary data -> Option A

4. Quick Check:

   Large binary data > 64KB = MEDIUMBLOB [OK]

Hint: Use MEDIUMBLOB for binary data > 64KB [OK]

Common Mistakes:

• Using fixed-length BINARY for large data
• Choosing VARCHAR or TEXT for binary files
• Underestimating BLOB size limits