SQL

Gagan Garg

What is a view and why we use it ? can we create nested views ?

2 Replies

Know the answer? Post it — somebody with the same question will find it here.

Howher Michael1y ago
Hmm, I think a view is basically like a saved query in SQL. You use it so you don’t have to write the same complex query over and over. And yeah, I’ve tried creating nested views before, it works, but you just have to be careful about performance if the layers get too deep.
0
Vijay Bansode1y ago
A View in SQL is like a saved query that acts like a virtual table.

Yes ? — you can create a view on top of another view.
```
-- First view
CREATE VIEW vw_SalesSummary AS
SELECT OrderID, CustomerID, TotalAmount
FROM Sales;

-- Nested view (uses first view)
CREATE VIEW vw_HighValueSales AS
SELECT * 
FROM vw_SalesSummary
WHERE TotalAmount > 10000;
```
But caution:
- Too many nested views can reduce performance because SQL Server has to expand and run all underlying queries.
- Debugging becomes harder when logic is buried inside multiple view layers.
- Sometimes SQL Server has a nesting limit (e.g., 32 levels max).
0