SQL Operators Made Easy for Beginners

SQL Operators Made Easy for Beginners

SQL (Structured Query Language) uses operators to perform operations on data. Here’s a simple guide to understand the basics:

1. Arithmetic Operators These are used for mathematical operations.

• + (Addition): Adds two numbers.

  SELECT 3 + 2; -- Result is 5

• - (Subtraction): Subtracts one number from another.

  SELECT 5 - 3; -- Result is 2

• (Multiplication): Multiplies two numbers. sql SELECT 4 2; -- Result is 8 ``
• / (Division): Divides one number by another. `sql SELECT 10 / 2; -- Result is 5 `
• % (Modulus): Returns the remainder of a division. `sql SELECT 10 % 3; -- Result is 1 `

1. Comparison Operators These are used to compare two values.

• = (Equal): Checks if two values are equal. `sql SELECT FROM employees WHERE salary = 50000; `
• != or <> (Not Equal): Checks if two values are not equal. `sql SELECT FROM employees WHERE department != 'HR'; `
• > (Greater Than): Checks if the left value is greater than the right value. `sql SELECT FROM employees WHERE age > 30; `
• < (Less Than): Checks if the left value is less than the right value. `sql SELECT FROM employees WHERE age < 25; `
• >= (Greater Than or Equal To): Checks if the left value is greater than or equal to the right value. `sql SELECT FROM employees WHERE experience >= 5; `
• <= (Less Than or Equal To): Checks if the left value is less than or equal to the right value. `sql SELECT FROM employees WHERE experience <= 2; `

1. Logical Operators These are used to combine multiple conditions.

• AND: Combines two or more conditions. All conditions must be true. `sql SELECT FROM employees WHERE age > 25 AND department = 'Finance'; `
• OR: Combines two or more conditions. At least one condition must be true. `sql SELECT FROM employees WHERE age < 30 OR department = 'HR'; `
• NOT: Reverses the result of a condition. `sql SELECT FROM employees WHERE NOT (age < 30); `

1. Between and In Operators

• BETWEEN: Selects values within a given range (inclusive). `sql SELECT FROM employees WHERE salary BETWEEN 30000 AND 50000; `
• IN: Checks if a value is within a set of values. `sql SELECT FROM employees WHERE department IN ('HR', 'Finance', 'IT'); `

1. LIKE and IS NULL Operators

• LIKE: Used for pattern matching. % represents zero or more characters, _ represents a single character. `sql SELECT FROM employees WHERE name LIKE 'J%'; -- Names starting with 'J' SELECT FROM employees WHERE name LIKE '_

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