In this syntax, the SELECT statement can have other clauses such as WHERE, JOIN, HAVING, and GROUP BY. However, to be compliant with the ANSI standard, they all support at least the major commands (such as
WHERE) in a similar manner. This tutorial supplements all explanations with clarifying examples.
Using the TOP PERCENT keyword
Only one of the conditions must be met for a result to be returned. All of the conditions must be met for the result to be returned. SELECT DISTINCT only returns data that is distinct — in other words, if there are duplicate records, it will return only one copy of each. You’ll use it pretty much every time you query data with SQL.
The PERCENT keyword indicates that the query returns the first N percentage of rows, where N is the result of the expression. Because the order of rows stored in a table is unspecified, the SELECT TOP statement is always used in conjunction with the ORDER BY clause. Therefore, basis sql the result set is limited to the first N number of ordered rows. The data in RDBMS is stored in database objects called tables. A table is a collection of related data entries and it consists of columns and rows. It shows the top N number of rows from the tables in the output.
Using the TOP keyword
ROW_NUMBER function helps to give temporary numbers to the result set of the query and it can be also used instead
of the TOP clauses. For example, the following query will return the first 4 rows of the Product table. The WITH TIES allows you to return more rows with values that match the last row in the limited result set. Note that WITH TIES may cause more rows to be returned than you specify in the expression.
The TOP clause allows us to limit the result set of the queries according to the number of rows or the percentage of
rows. In general, the TOP and ORDER BY construction are used together. Otherwise, the TOP clause will return the N
number of rows in an uncertain order.
Suppose we don’t want to get Customers whose Age is less than 22 in our result set and want the first 2 employees to have low Scores. LEFT JOIN selects records from the left table that match records in the right table. For example, the code below would update the age of any customer named Bob in the customers table to 56. For example, in https://deveducation.com/ the code below, we’re selecting a column called name from a table called customers. This article provides guidance on how to identify the most resource intensive SQL statements in a database for tuning purposes. This SQL Server SELECT TOP example would select the first 5 records from the employees table where the last_name is ‘Anderson’.