SQL Programming
  • Introduction to SQL
  • Data Definition Language
    • DATA TYPES
    • CREATE DATABASE
    • DROP DATABASE
    • CREATE TABLE Statement
    • CONSTRAINTS
      • SQL PRIMARY KEY Constraint
      • SQL NOT NULL Constraint
      • SQL UNIQUE Constraint
      • SQL FOREIGN KEY Constraint
      • SQL DEFAULT Constraint
      • SQL CHECK Constraint
    • DROP & TRUNCATE TABLE Statement
    • ALTER TABLE Statement
    • AUTO INCREMENT Field
    • SQL SELECT INTO Statement
    • CREATE INDEX
    • DDL Practice Problems
  • Data Manipulation Language
    • INSERT INTO Statement
    • INSERT INTO SELECT Statement
    • DELETE Statement
    • UPDATE Statement
    • DML Practice Problems
  • SQL NULL Values
  • SQL Comments
  • Data Query Language
    • SQL SELECT DISTINCT Statement
    • SQL WHERE Clause
      • SQL And, Or, Not (Logical Operators)
      • SQL Wildcards
      • SQL LIKE Operator
      • SQL IN Operator
      • SQL BETWEEN Operator
      • SQL WHERE Exercises
    • SQL TOP CLAUSE
    • SQL Order By
    • SQL Server Scalar Functions (Non-aggregate)
      • SQL MIN() and MAX()
      • SQL COUNT(), AVG() and SUM() Functions
      • Functions Problems
    • SQL ISNULL Functions
    • SQL Aliases
    • SQL CASE Statement
    • SQL SET Operator
    • SQL GROUP BY Statement
    • SQL HAVING Clause
    • Analytical Function
    • SQL Joins
      • SQL INNER JOIN Keyword
      • SQL LEFT JOIN Keyword
      • SQL RIGHT JOIN Keyword
      • SQL FULL OUTER JOIN Keyword
      • SQL Self JOIN
      • SQL CROSS JOIN
    • SQL Subqueries
    • SQL EXISTS Operator
    • SQL ANY and ALL Operators
  • CREATE VIEWS
  • Common Table Expressions (CTE)
  • Data Control Language
  • SQL Stored Procedures for SQL Server
  • Practice Papers
  • SQL PROJECT
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  • The SQL SELECT Statement
  • Demo Database
  • SELECT Column
  • SELECT *
  • SQL Order of Execution

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Data Query Language

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Last updated 6 years ago

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The SQL SELECT Statement

The SELECT statement is used to retrieve data from a database.

The data returned is stored in a result table, called the result-set.

Basic Syntax:

SELECT column1,column2 FROM table_name 
column1 , column2: names of the fields of the table
table_name: from where we want to fetch

Demo Database

Below is a selection from the "Consumer" table in a sample database:

SELECT Column

The following SQL statement selects the "Customer Name" and "City" columns from the "Consumer" table:

SELECT CustomerName, City FROM Consumer;

SELECT *

The following SQL statement selects all the columns from the "Consumer" table:

SELECT * FROM Consumer;

SQL Order of Execution

The SQL order of execution defines the order in which the clauses of a query are evaluated. Some of the most common query challenges I run into could be easily avoided with a clearer understanding of the SQL order of execution, sometimes called the order of operations. Understanding query order can help you diagnose why a query won't run, and even more frequently will help you optimize your queries to run faster. In today's modern world, SQL query planners can do all sorts of tricks to make queries run more efficiently, but they must always reach the same final answer as a query that is executed per the standard order of execution. This order is: