The SELECT TOP clause in SQL is used to restrict the variety of rows returned by a question. It’s generally used with the SELECT assertion to retrieve a specified variety of rows from the outcome set. The syntax varies barely between completely different database administration techniques (DBMS), however I’ll present a basic overview.
In SQL Server and MS Entry, the syntax is:
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SELECT TOP (quantity) column1, column2, ... FROM table_name WHERE situation; |
For instance, if you wish to retrieve the highest 5 rows from a desk named staff, you should use:
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SELECT TOP 5 * FROM staff; |
In MySQL, you should use the LIMIT clause:
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SELECT column1, column2, ... FROM table_name WHERE situation LIMIT quantity; |
For instance:
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SELECT * FROM staff LIMIT 5; |
It’s vital to notice that the precise syntax might range, and a few database techniques might have their very own methods of attaining related outcomes (e.g., utilizing FETCH FIRST in some circumstances). At all times check with the documentation of the precise database administration system you might be working with for exact particulars on syntax and performance.
FETCH FIRST
The FETCH FIRST clause in SQL is used to restrict the variety of rows returned by a question. It’s much like the LIMIT clause in MySQL and PostgreSQL. The FETCH FIRST clause is commonly used together with the ORDER BY clause to specify the ordering of the outcome set earlier than limiting the variety of rows.
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— Retrieve the high 3 orders with the highest complete quantity SELECT OrderID, CustomerID, TotalAmount FROM Orders ORDER BY TotalAmount DESC FETCH FIRST 3 ROWS ONLY;
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