SQL Select Statement

SQL Select statement can be used to select or retrieve records from a database table or multiple tables as mentioned below.

  • Retrieve data from one or more tables using a single SELECT statement.
  • Retrieve data from all columns or selected columns from a table.
  • Retrieve data from specific records that satisfy a certain condition or a combination of conditions, using conditional clauses.

In the previous chapter, we used the INSERT statement to insert records into a table.

Now, let's see how to retrieve the records using the SELECT statement.

Syntax

Here is the basic syntax of a SELECT statement.

  • The table name is represented as table_name.
  • The table columns are represented as column1, column2, and ao on.
  • The asterisk * is a wildcard character that means everything, means all columns.

Use the below query to retrieve data from all columns.

SELECT * FROM table_name;

Use the below query to retrieve data from specific columns.

SELECT column1_name, column2_name, columnN_name FROM table_name;

Select All from Table

Use the below query to retrieve data from all columns of a table.

Run this on IDE

SELECT * FROM employees;

After successful execution, the output looks something like this.

employee_id employee_name gender birth_date hire_date salary
1 Robin Hood M 1990-10-10 2010-10-15 25000
2 Tony Blank M 1982-08-07 2010-01-05 89000
3 Andrew Russel M 1998-05-04 2012-02-20 28000

Select Columns from Table

Use the below query to retrieve data from specific columns of a table, which can be used when we don't need data from all the columns.

Run this on IDE

SELECT employee_id, employee_name, hire_date, salary FROM employees;

After successful execution, the output looks something like this.

employee_id employee_name hire_date salary
1 Robin Hood 2010-10-15 25000
2 Tony Blank 2010-01-05 89000
3 Andrew Russel 2012-02-20 28000

Select from Multiple Tables

You will learn about this in a separate chapter.

Overall

We now know how to create and execute a SELECT statement to retrieve data from a table.

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