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‎docs/sql/SQL-basics/operators.md‎

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---
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id: sql-operators
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title: SQL Operators
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sidebar_label: SQL Operators
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sidebar_position: 8
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tags: [sql, operators, database, relational-databases]
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description: In this super beginner-friendly guide, you’ll learn about SQL operators—the tools that help you do math, compare things, and make decisions in your queries!
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keywords: [sql, operators, sql tutorial, sql basics, database management, relational databases, sql operators tutorial, sql for beginners, sql in 2025]
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---
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## 📙 Welcome to SQL Operators!
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Hey there, SQL beginner! Operators are like magic symbols in SQL that let you add numbers, compare values, or combine conditions. Think of them as the plus (+) or equals (=) signs you use in math, but for databases. They’re super useful in queries, especially in WHERE clauses to filter data. We’ll use a simple `students` table (with columns like `id`, `name`, `age`, `marks`, and `city`) to explain everything with easy examples. Let’s dive in step by step!
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### 📘 What Are Operators?
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Operators are symbols or keywords that perform operations on data. They help you:
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- Do calculations (arithmetic operators).
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- Compare values (comparison operators).
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- Combine conditions (logical operators).
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- Check for patterns or ranges (special operators like LIKE or BETWEEN).
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You’ll often use them in SELECT statements to filter or calculate results.
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> **Pro Tip**: Operators make your queries smarter—practice them to find exactly the data you need!
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### 📘 Arithmetic Operators (Math in SQL!)
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These operators let you add, subtract, multiply, divide, or find remainders. They’re great for calculating things like total marks.
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The main ones:
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- **+** (Addition): Adds numbers.
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- **-** (Subtraction): Subtracts numbers.
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- *** (Multiplication): Multiplies numbers.
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- **/** (Division): Divides numbers.
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- **%** (Modulus): Gives the remainder.
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**Example**:
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:::info
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<Tabs>
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<TabItem value="SQL Code" label="SQL Code">
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```sql title="Using Arithmetic Operators"
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-- Assume students table has marks column
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SELECT id, name, marks + 10 AS bonus_marks -- Add 10 to marks
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FROM students
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WHERE marks > 80;
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```
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</TabItem>
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<TabItem value="Output" label="Output">
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| id | name | bonus_marks |
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|----|-------|-------------|
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| 1 | Alice | 95 |
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| 2 | Bob | 102 |
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</TabItem>
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</Tabs>
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:::
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> **What NOT to Do**: Don’t divide by zero (e.g., marks / 0)—it’ll cause an error. Always check for zero first!
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### 🔄 Comparison Operators (Checking If Things Match!)
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These help you compare values, like finding students older than 18. They’re used in WHERE to filter rows.
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The main ones:
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- **=** (Equal): Checks if equal.
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- **!=** or **<>** (Not Equal): Checks if not equal.
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- **>** (Greater Than): Bigger than.
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- **<** (Less Than): Smaller than.
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- **>=** (Greater Than or Equal): Bigger or same.
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- **<=** (Less Than or Equal): Smaller or same.
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**Example**:
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:::info
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<Tabs>
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<TabItem value="SQL Code" label="SQL Code">
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```sql title="Using Comparison Operators"
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SELECT id, name, age
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FROM students
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WHERE age >= 18 AND marks > 80; -- Adults with high marks
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```
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</TabItem>
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<TabItem value="Output" label="Output">
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| id | name | age |
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|----|-------|-----|
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| 1 | Alice | 20 |
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| 2 | Bob | 22 |
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</TabItem>
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</Tabs>
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:::
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> **What NOT to Do**: Don’t use = for strings without quotes (e.g., WHERE city = Delhi)—always quote text like 'Delhi' to avoid errors!
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### 📘 Logical Operators (Combining Conditions!)
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These let you mix multiple conditions, like finding students who are young OR high-scorers.
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The main ones:
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- **AND**: Both conditions must be true.
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- **OR**: At least one condition is true.
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- **NOT**: Reverses a condition (true becomes false).
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**Example**:
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:::info
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<Tabs>
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<TabItem value="SQL Code" label="SQL Code">
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```sql title="Using Logical Operators"
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SELECT id, name, marks
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FROM students
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WHERE (marks > 90 OR age < 18) AND NOT city = 'Delhi'; -- High marks or young, not from Delhi
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```
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</TabItem>
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<TabItem value="Output" label="Output">
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| id | name | marks |
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|----|-------|-------|
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| 3 | Carol | 95 |
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| 4 | Dave | 45 |
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</TabItem>
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</Tabs>
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:::
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> **What NOT to Do**: Don’t overuse AND/OR without parentheses (e.g., A AND B OR C)—it can confuse the order. Use (A AND B) OR C to be clear!
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### 🔄 Special Operators (Fancy Filters!)
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These are extra helpful for patterns or ranges:
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- **BETWEEN**: Checks a range (e.g., marks BETWEEN 70 AND 90).
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- **IN**: Checks against a list (e.g., city IN ('Delhi', 'Mumbai')).
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- **LIKE**: Pattern matching (e.g., name LIKE 'A%' for names starting with A).
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- **IS NULL / IS NOT NULL**: Checks for empty values.
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**Example**:
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:::info
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<Tabs>
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<TabItem value="SQL Code" label="SQL Code">
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```sql title="Using Special Operators"
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SELECT id, name, city
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FROM students
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WHERE marks BETWEEN 80 AND 90 AND name LIKE 'A%'; -- Marks 80-90, name starts with A
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```
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</TabItem>
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<TabItem value="Output" label="Output">
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| id | name | city |
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|----|-------|-------|
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| 1 | Alice | Mumbai|
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</TabItem>
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</Tabs>
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:::
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> **What NOT to Do**: Don’t use LIKE without % or _ wildcards (e.g., name LIKE 'Alice')—it’s the same as = and less efficient for patterns!
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## ✅ What You’ve Learned
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You’re a SQL operator pro now! You’ve explored:
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- **Arithmetic Operators**: +, -, *, /, % for calculations.
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- **Comparison Operators**: =, !=, >, etc., for checks.
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- **Logical Operators**: AND, OR, NOT for combining.
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- **Special Operators**: BETWEEN, IN, LIKE, IS NULL for advanced filters.
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Practice by writing queries with these operators on a sample table. Avoid the "What NOT to Do" tips to keep your queries error-free and fast!
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---

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