What results does an SQL query return?

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What results does an SQL query return?

The SQL SELECT statement returns a result set of records, from one or more tables. A SELECT statement retrieves zero or more rows from one or more database tables or database views. In most applications, SELECT is the most commonly used data manipulation language (DML) command.

What are the functions of query and how it produces the result?

A query function is a mathematical expression evaluated against each item returned by a query, and whose output is stored in a dynamic, temporary field generated at query time.

How does SQL return data?

To cover the area of how data is retrieved, when you make a call to SQL to retrieve some data SQL will first check to see if the data pages you are looking for is in memory in order to speed up the delivery of data. If not then it will retrieve this data from the data files on disk and read them back into memory.

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How can a function return a value in SQL?

Syntax:

  1. DECLARE @ReturnValue INT.
  2. EXEC @ReturnValue = < Store Procedure Name > < Parameters > Select @ReturnValue.
  3. Example: DECLARE @ReturnValue INT.
  4. EXEC @ReturnValue = CheckStudentId 34.
  5. SELECT @ReturnValue.

What is query return?

Query objects are composable, meaning that you can return a query from a method. Objects that represent queries do not store the resulting collection, but rather the steps to produce the results when needed. Therefore any return value or out parameter of a method that returns a query must also have that type.

What is the function of the query commands?

Use the query command to search for objects in the database. Rational® Synergy evaluates a query expression during a search operation. The query expression can consist of any query clause from query-related options combined with any query_string argument.

Which SQL statement is used to return only different values?

The SQL SELECT DISTINCT Statement
The SQL SELECT DISTINCT Statement The SELECT DISTINCT statement is used to return only distinct (different) values. Inside a table, a column often contains many duplicate values; and sometimes you only want to list the different (distinct) values.

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Why are SQL queries important?

SQL (Structured Query Language) is a standard database language that is used to create, maintain and retrieve relational databases. Started in the 1970s, SQL has become a very important tool in a data scientist’s toolbox since it is critical in accessing, updating, inserting, manipulating and modifying data.

How do I query a function in SQL Server?

In this syntax:

  1. First, specify the name of the function after the CREATE FUNCTION keywords.
  2. Second, specify a list of parameters surrounded by parentheses after the function name.
  3. Third, specify the data type of the return value in the RETURNS statement.