Year-Over-Year (YOY) Growth in SQL: The Ultimate Guide with Examples

Table of Contents

1. Introduction
2. YOY Growth Formula
3. Why Use YOY Growth?
4. How YOY Growth Works (Step-by-Step)
5. Practical Use Cases
   • Data Model and Sample Data
   • Revenue Growth
   • Customer Growth
   • Profitability and Cost Efficiency
   • Market Share and Performance
6. YOY vs. MoM vs. CAGR
7. How to Calculate YOY Growth in SQL
8. Common Mistakes and Best Practices
9. Visualizing YOY Growth with a Database Schema
10. Conclusion

Introduction

Year-over-Year (YOY) growth is a key metric used to measure business performance by comparing values from one period to the same period one year earlier. It eliminates seasonal fluctuations and highlights long-term trends.

Businesses rely on YOY growth to track revenue, customer base, profit margins, and market expansion. Understanding YOY growth helps companies make data-driven decisions and adjust their strategies based on long-term performance.

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YOY Growth Formula

The standard formula for calculating YOY growth is:

YOY Growth (%) = ((Current Year Value - Previous Year Value) / Previous Year Value) × 100

Example Calculation:

A company’s revenue in 2023 was $1,200,000, compared to $1,000,000 in 2022. The YOY growth is:

SELECT 2023 AS Year, 1200000 AS Revenue,
       1000000 AS Prev_Year_Revenue,
       ((1200000 - 1000000) / 1000000) * 100 AS YOY_Growth;

Output:

Year	Revenue ($)	Prev Year Revenue ($)	YOY Growth (%)
2023	1,200,000	1,000,000	20.0%

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Data Model and Sample Data

To analyze YOY growth effectively, we use the following relational schema:

Sample Input Data

Year	Revenue ($)	Customers	Net Profit ($)	Market Share (%)
2022	1,000,000	5,000	200,000	10.0
2023	1,200,000	6,000	250,000	12.0
2024	1,440,000	7,200	312,500	14.4

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Practical Use Cases

1. Revenue Growth

Tracking revenue growth is essential for understanding business performance over time.

SQL Query:

SELECT year, revenue,
       LAG(revenue, 1) OVER (ORDER BY year) AS prev_year_revenue,
       ((revenue - LAG(revenue, 1) OVER (ORDER BY year)) / LAG(revenue, 1) OVER (ORDER BY year)) * 100 AS YOY_Growth
FROM financials;

Output:

Year	Revenue ($)	Prev Year Revenue ($)	YOY Growth (%)
2022	1,000,000	NULL	NULL
2023	1,200,000	1,000,000	20.0%
2024	1,440,000	1,200,000	20.0%

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2. Customer Growth

Analyzing YOY customer growth helps businesses measure expansion.

SQL Query:

SELECT year, customers,
       LAG(customers, 1) OVER (ORDER BY year) AS prev_year_customers,
       ((customers - LAG(customers, 1) OVER (ORDER BY year)) / LAG(customers, 1) OVER (ORDER BY year)) * 100 AS YOY_Growth
FROM financials;

Output:

Year	Customers	Prev Year Customers	YOY Growth (%)
2022	5,000	NULL	NULL
2023	6,000	5,000	20.0%
2024	7,200	6,000	20.0%

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3. Profitability and Cost Efficiency

Understanding profitability trends helps assess financial health.

SQL Query:

SELECT year, net_profit,
       LAG(net_profit, 1) OVER (ORDER BY year) AS prev_year_profit,
       ((net_profit - LAG(net_profit, 1) OVER (ORDER BY year)) / LAG(net_profit, 1) OVER (ORDER BY year)) * 100 AS YOY_Growth
FROM financials;

Output:

Year	Net Profit ($)	Prev Year Profit ($)	YOY Growth (%)
2022	200,000	NULL	NULL
2023	250,000	200,000	25.0%
2024	312,500	250,000	25.0%

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4. Market Share and Performance

Evaluating market share growth helps measure competitiveness.

SQL Query:

SELECT year, market_share,
       LAG(market_share, 1) OVER (ORDER BY year) AS prev_year_share,
       ((market_share - LAG(market_share, 1) OVER (ORDER BY year)) / LAG(market_share, 1) OVER (ORDER BY year)) * 100 AS YOY_Growth
FROM financials;

Output:

Year	Market Share (%)	Prev Year Share (%)	YOY Growth (%)
2022	10.0	NULL	NULL
2023	12.0	10.0	20.0%
2024	14.4	12.0	20.0%

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YOY vs. MoM vs. CAGR

While YOY growth is valuable for annual comparisons, other metrics serve different purposes:

1. Month-over-Month (MoM): Measures short-term growth between consecutive months
2. Compound Annual Growth Rate (CAGR): Calculates the average annual growth rate over multiple years

How to Calculate YOY Growth in SQL

SQL provides powerful tools for YOY calculations:

1. Window Functions: Use LAG() to access previous year’s values
2. Self Joins: Join a table with itself to compare years
3. CTEs: Create temporary result sets for complex calculations

Common Mistakes and Best Practices

1. Handle NULL Values: Use COALESCE or ISNULL for first-year calculations. Learn more about handling NULL values in our comprehensive COALESCE guide.
2. Data Quality: Ensure consistent date formats and complete datasets
3. Seasonal Adjustments: Consider seasonal patterns in your analysis
4. Percentage Formatting: Format results appropriately for reporting

Visualizing YOY Growth with a Database Schema

Try these examples yourself using RunSQL’s SQL playground. Our platform makes it easy to:

1. Create tables using DBML
2. Import sample data
3. Run and share SQL queries
4. Visualize results

Conclusion

YOY growth analysis is crucial for business intelligence and decision-making. By mastering SQL calculations and understanding best practices, you can effectively track and analyze performance metrics over time.

Ready to practice YOY calculations? Try RunSQL for free and experiment with these examples in a live environment.