MS-SQL vs MySQL Queries – Difference in DDL, DML, SELECT

MS-SQL vs MySQL queries are a common comparison for developers working with relational databases. Both Microsoft SQL Server (MS-SQL) and MySQL are widely used systems that follow the SQL (Structured Query Language) standard. However, their specific implementations and syntax often differ. These differences in queries can create challenges, especially when switching between the two platforms.

In this article, we will explore the differences in MS-SQL vs MySQL queries with a focus on Data Definition Language (DDL), Data Manipulation Language (DML), and SELECT queries. Clear examples will highlight how these commands work differently in each system.

1. Data Definition Language (DDL)

DDL commands define and manage database structures such as tables. Let’s compare MS-SQL vs MySQL queries for creating a table.

Example 1: Creating a Table

MS-SQL:

CREATE TABLE Employees (
    EmpID INT PRIMARY KEY IDENTITY(1,1),
    EmpName VARCHAR(100) NOT NULL,
    Salary DECIMAL(10,2),
    HireDate DATETIME DEFAULT GETDATE()
);

MySQL:

CREATE TABLE Employees (
    EmpID INT PRIMARY KEY AUTO_INCREMENT,
    EmpName VARCHAR(100) NOT NULL,
    Salary DECIMAL(10,2),
    HireDate DATETIME DEFAULT CURRENT_TIMESTAMP
);

Key Differences in DDL:

• MS-SQL uses IDENTITY for auto-increment columns, while MySQL uses AUTO_INCREMENT.
• MS-SQL uses GETDATE() for default date values, whereas MySQL uses CURRENT_TIMESTAMP.

2. Data Manipulation Language (DML)

DML commands handle inserting, updating, and deleting records. Most MS-SQL vs MySQL queries look similar, but there are some subtle differences.

Example 2: Inserting Data

INSERT INTO Employees (EmpName, Salary)
VALUES ('John Doe', 55000.50);

Works the same in both MS-SQL and MySQL.

Example 3: Updating Data

UPDATE Employees
SET Salary = Salary + 5000
WHERE EmpID = 1;

Syntax is identical in both systems.

Example 4: Deleting Data with a Limit

MS-SQL:

DELETE TOP (1)
FROM Employees
WHERE Salary < 30000;

MySQL:

DELETE FROM Employees
WHERE Salary < 30000
LIMIT 1;

Key Difference in DML:

• MS-SQL limits rows with TOP (n).
• MySQL uses the LIMIT n clause.

3. SELECT Queries

SELECT statements are used to retrieve data. This is where differences in MS-SQL vs MySQL queries become clear.

Example 5: Selecting Top N Rows

MS-SQL:

SELECT TOP 5 EmpName, Salary
FROM Employees
ORDER BY Salary DESC;

MySQL:

SELECT EmpName, Salary
FROM Employees
ORDER BY Salary DESC
LIMIT 5;

Difference:

• MS-SQL uses TOP n.
• MySQL uses LIMIT n.

Example 6: String Concatenation

MS-SQL:

SELECT EmpName + ' earns ' + CAST(Salary AS VARCHAR)
FROM Employees;

MySQL:

SELECT CONCAT(EmpName, ' earns ', Salary)
FROM Employees;

Difference:

• MS-SQL uses + for string concatenation.
• MySQL uses CONCAT().

Example 7: Current Date and Time

MS-SQL:

SELECT GETDATE() AS CurrentDate;

MySQL:

SELECT NOW() AS CurrentDate;

Difference:

• MS-SQL uses GETDATE().
• MySQL uses NOW().

4. Practical Tips for Developers

When working with MS-SQL vs MySQL queries, keep these tips in mind:

• Always check for differences in auto-increment, string concatenation, and date functions.
• For cross-platform applications, avoid using vendor-specific functions when possible.
• Test queries in both systems before deployment to prevent unexpected errors.

MS-SQL vs MySQL Queries: Which Should You Choose?

Selecting between MS-SQL and MySQL depends on your project’s specific needs. Both are robust relational database management systems, but each has distinct strengths.

Advantages of MS-SQL:

• Seamless integration with the Microsoft ecosystem (such as Azure and .NET applications)
• Advanced security features and sophisticated transaction handling
• Ideal for large-scale, enterprise-level solutions

Advantages of MySQL:

• Open-source, with broad platform support
• Lightweight and easy to deploy, making it popular for web applications
• Backed by a vast community and optimized for read-intensive workloads

In summary, MS-SQL is often favored for complex, enterprise-grade projects that require advanced features and Microsoft integration, while MySQL is typically selected for web-based or startup projects due to its simplicity, flexibility, and lower cost.

Conclusion

Although MS-SQL vs MySQL queries share many similarities, they differ in crucial areas such as auto-increment handling, row limiting, string concatenation, and date functions. For simple DML operations like INSERT, UPDATE, and DELETE, the syntax is almost identical. However, developers transitioning between MS-SQL and MySQL should pay attention to subtle differences in DDL and SELECT queries to avoid compatibility issues.

By mastering these differences, you can write portable SQL queries, streamline development, and make your applications more database-agnostic.