Introduction

In this video, we will learn how to use the SELECT and WHERE statements in PostgreSQL, along with conditional and logical operators. These concepts are fundamental to querying and filtering data in a database.

SELECT Statement

The SELECT statement is used to retrieve data from a table. The basic syntax is:

SELECT column1, column2, ...
FROM table_name;

You can select specific columns or use * to select all columns. For example:

SELECT first_name, last_name 
FROM employees;

This will return the first_name and last_name columns from the employees table.

WHERE Clause

The WHERE clause is used to filter rows based on a specified condition. The basic syntax is:

SELECT column1, column2, ...
FROM table_name
WHERE condition;

The condition can be a comparison, such as:

SELECT *
FROM employees
WHERE department = 'IT';

This will return all columns from the employees table where the department is 'IT'.

Conditional Operators

PostgreSQL supports various conditional operators that can be used in the WHERE clause: -  = (equal to)

-  <> or  !=  (not equal to)

-  >  (greater than)

-  <  (less than)

-   >=  (greater than or equal to)

-  <=  (less than or equal to)

For example:

SELECT *
FROM employees
WHERE salary > 50000;

This will return all employees with a salary greater than 50,000.

Logical Operators

Logical operators can be used to combine multiple conditions in the WHERE clause: -  AND: Both conditions must be true

-  OR : At least one condition must be true

-  NOT : Negates a condition Here is a suggested text content for your video lecture on SELECT & WHERE Statements + Conditional And Logical Operators in PostgreSQL, with examples:

For example:

SELECT name,color FROM tableName WHERE name=’Vishal’  AND color=’Blue’ ;<br>

Conclusion

In this video, we covered the basics of using the SELECT and WHERE statements in PostgreSQL, along with conditional and logical operators. These concepts are essential for querying and filtering data in a database. Practice writing SQL queries using these techniques to become more comfortable with them.