Data type in SQL

🧠 What are Data Types in SQL?

In SQL, data types define what kind of data can be stored in each column of a table—such as numbers, text, dates, or true/false values.

When you create a table, you must choose the correct data type for each column.

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🔢 1. Numeric Data Types

Used to store numbers, like marks, price, quantity, etc.

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📝 2. Character/String Data Types

Used to store text like names, addresses, etc.

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📅 3. Date and Time Data Types

Used to store date and/or time.

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✅ 4. Boolean Data Type

Stores true/false (yes/no) values.

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🧪 5. Other Data Types (Special Use)

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🧾 Example Table With Data Types

Here’s an example of a table that uses different types of data:

CREATE TABLE Students (
    StudentID INT PRIMARY KEY,         -- number (whole)
    Name VARCHAR(50),                  -- text
    DOB DATE,                          -- date
    Score DECIMAL(5,2),                -- number with decimal
    IsActive BOOLEAN                   -- true/false
);

This table will store:

• StudentID: Unique number for each student

• Name: Up to 50 characters

• DOB: Date of birth

• Score: Like marks (e.g., 88.75)

• IsActive: Whether the student is active or not (TRUE/FALSE)

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📌 Quick Summary Table

✅ INSERT Commands (Add Rows)

Here are a few examples inserting different students:

INSERT INTO Students (StudentID, Name, DOB, Score, IsActive)
VALUES (1, 'Amit Singh', '2002-05-10', 89.75, TRUE);

INSERT INTO Students (StudentID, Name, DOB, Score, IsActive)
VALUES (2, 'Priya Sharma', '2001-11-22', 92.50, TRUE);

INSERT INTO Students (StudentID, Name, DOB, Score, IsActive)
VALUES (3, 'Rahul Mehta', '2003-03-15', 76.00, FALSE);

INSERT INTO Students (StudentID, Name, DOB, Score, IsActive)
VALUES (4, 'Anjali Verma', '2002-08-01', 84.25, TRUE);