Why WHERE with BETWEEN range in SQL? - Purpose & Use Cases

The Big Idea

What if you could find all data in a range with just one simple command?

The Scenario

Imagine you have a big list of sales records on paper, and you want to find all sales made between $100 and $200. You have to scan each record one by one, checking the amount manually.

The Problem

This manual checking is slow and tiring. You might miss some records or make mistakes while comparing numbers. It's hard to keep track and easy to get confused.

The Solution

Using WHERE with BETWEEN range in SQL lets you quickly ask the database to find all records within a range. It does the hard work instantly and perfectly, so you get the right results fast.

Before vs After

✗ Before

Check each record: if amount >= 100 and amount <= 200 then select

✓ After

SELECT * FROM sales WHERE amount BETWEEN 100 AND 200;

What It Enables

You can easily filter data by ranges, making your searches fast, accurate, and simple.

Real Life Example

A store manager wants to see all orders with total price between $50 and $150 to plan discounts. Using BETWEEN saves hours of manual work.

Key Takeaways

Manually checking ranges is slow and error-prone.

WHERE with BETWEEN quickly filters data within a range.

This makes data searching faster and more reliable.

Practice

1. What does the SQL clause WHERE column BETWEEN 10 AND 20 do?

easy

A. Selects rows where the column value is greater than 10 but less than 20, excluding 10 and 20

B. Selects rows where the column value is between 10 and 20, including 10 and 20

C. Selects rows where the column value is exactly 10 or exactly 20 only

D. Selects rows where the column value is less than 10 or greater than 20

Solution

1. Step 1: Understand BETWEEN clause behavior

   The BETWEEN clause includes both the start and end values in the range.

2. Step 2: Apply to the given range 10 to 20

   This means values equal to 10, 20, or any number between them are selected.

3. Final Answer:

   Selects rows where the column value is between 10 and 20, including 10 and 20 -> Option B

4. Quick Check:

   BETWEEN includes boundaries = B [OK]

Hint: BETWEEN includes both start and end values [OK]

Common Mistakes:

• Thinking BETWEEN excludes boundary values
• Confusing BETWEEN with > and < operators
• Assuming BETWEEN works only with numbers

2. Which of the following is the correct syntax to select rows where age is between 18 and 30?

easy

A. SELECT * FROM users WHERE age BETWEEN (18 AND 30);

B. SELECT * FROM users WHERE age BETWEEN 18 TO 30;

C. SELECT * FROM users WHERE age BETWEEN 18, 30;

D. SELECT * FROM users WHERE age BETWEEN 18 AND 30;

Solution

1. Step 1: Recall correct BETWEEN syntax

   The correct syntax uses BETWEEN start AND end without commas or parentheses.

2. Step 2: Check each option

   SELECT * FROM users WHERE age BETWEEN 18 AND 30; uses correct syntax: BETWEEN 18 AND 30. Others have syntax errors.

3. Final Answer:

   SELECT * FROM users WHERE age BETWEEN 18 AND 30; -> Option D

4. Quick Check:

   BETWEEN ... AND ... syntax = D [OK]

Hint: BETWEEN always uses AND, never TO or commas [OK]

Common Mistakes:

• Using TO instead of AND
• Adding commas between values
• Using parentheses around BETWEEN clause

3. Given the table products with a column price, what rows will this query return?

SELECT * FROM products WHERE price BETWEEN 50 AND 100;

Assume the prices in the table are: 45, 50, 75, 100, 120.

medium

A. Rows with prices 50, 75, and 100

B. Rows with prices 45, 50, 75, 100, and 120

C. Rows with prices 75 and 100 only

D. Rows with prices 50 and 100 only

Solution

1. Step 1: Identify the range in BETWEEN clause

   The query filters prices between 50 and 100, including both 50 and 100.

2. Step 2: Check which prices fall in this range

   Prices 50, 75, and 100 are within the range; 45 and 120 are outside.

3. Final Answer:

   Rows with prices 50, 75, and 100 -> Option A

4. Quick Check:

   BETWEEN includes boundaries, so 50 and 100 included = A [OK]

Hint: BETWEEN includes start and end values in results [OK]

Common Mistakes:

• Excluding boundary values 50 and 100
• Including values outside the range like 45 or 120
• Confusing BETWEEN with > and < operators

4. Identify the error in this SQL query:

SELECT * FROM orders WHERE order_date BETWEEN '2023-01-01' TO '2023-01-31';

medium

A. Using TO instead of AND in BETWEEN clause

B. Dates should not be in quotes

C. BETWEEN cannot be used with dates

D. Missing semicolon at the end

Solution

1. Step 1: Check BETWEEN syntax

   BETWEEN requires AND between the two values, not TO.

2. Step 2: Validate other parts

   Dates in quotes are correct, BETWEEN works with dates, and semicolon is optional in many systems.

3. Final Answer:

   Using TO instead of AND in BETWEEN clause -> Option A

4. Quick Check:

   BETWEEN uses AND, not TO = A [OK]

Hint: BETWEEN always uses AND, never TO [OK]

Common Mistakes:

• Replacing AND with TO in BETWEEN
• Thinking dates can't be quoted
• Assuming semicolon is mandatory

5. You want to select employees hired between January 1, 2020, and December 31, 2022, inclusive. Which query correctly uses BETWEEN and also excludes employees hired on weekends?

SELECT * FROM employees WHERE hire_date BETWEEN '2020-01-01' AND '2022-12-31' AND EXTRACT(DOW FROM hire_date) NOT IN (0,6);

What does this query do?

hard

A. Selects employees hired between the dates including weekends

B. Selects employees hired only on weekends between the dates

C. Selects employees hired between the dates excluding weekends

D. Syntax error due to EXTRACT usage

Solution

1. Step 1: Understand BETWEEN usage

   The query selects employees hired from 2020-01-01 to 2022-12-31 inclusive.

2. Step 2: Analyze EXTRACT(DOW FROM hire_date) condition

   EXTRACT(DOW) returns day of week (0=Sunday, 6=Saturday). NOT IN (0,6) excludes weekends.

3. Step 3: Combine conditions

   Only employees hired on weekdays within the date range are selected.

4. Final Answer:

   Selects employees hired between the dates excluding weekends -> Option C

5. Quick Check:

   BETWEEN + weekday filter = C [OK]

Hint: Use BETWEEN for range and filter weekdays with EXTRACT [OK]

Common Mistakes:

• Assuming BETWEEN excludes boundaries
• Confusing day numbers for weekend days
• Thinking EXTRACT causes syntax error