Why should you care?

Wrong types waste space or break money math — DECIMAL for currency, not FLOAT; DATETIME2 over legacy DATETIME for new work.

See it live — copy this example

Run in SQL Server Management Studio (SSMS) or Azure Data Studio.

USE DataVerse;
IF OBJECT_ID(N'dbo.Products', N'U') IS NOT NULL DROP TABLE dbo.Products;
CREATE TABLE dbo.Products (
    ProductId   INT IDENTITY(1,1) PRIMARY KEY,
    Sku         VARCHAR(32) NOT NULL,
    Name        NVARCHAR(200) NOT NULL,
    PriceInr    DECIMAL(10,2) NOT NULL,
    InStock     BIT NOT NULL CONSTRAINT DF_Products_InStock DEFAULT (1),
    ListedOn    DATE NOT NULL
);
INSERT INTO dbo.Products (Sku, Name, PriceInr, ListedOn)
VALUES ('HD-100', N'Noise Cancelling Headphones', 4999.00, '2026-01-15');
SELECT ProductId, Sku, PriceInr, InStock FROM dbo.Products;

What happened?

• DECIMAL(10,2) keeps paise exact.
• BIT stores true/false stock.
• DATE stores calendar day without time.
• NVARCHAR holds Unicode product names.

Practice next

1. Create dbo.Products with the script.
2. Insert a second product with InStock = 0.
3. Query WHERE PriceInr > 1000.
4. Add WeightGrams INT NULL and update one row.
5. Change ListedOn to DATETIME2 and insert with a time.

Remember

Pick types that match real data. Money → DECIMAL; flags → BIT; text → NVARCHAR. Bad types cause bugs and wasted storage.

Catalog price must not drift

DataVerse Products.PriceInr is DECIMAL(10,2) for GST invoices.

Outcome: Invoice totals match the cart to the paisa.