SQL

SQL stands for Structured Query Language.

SQL is used to access and manipulate a database.

MySQL is a program that understands SQL.

SQL can:

• insert, update, or delete records in a database.
• create new databases, tables, stored procedures and views.
• retrieve data from a database, etc.

SELECT

The SELECT statement is used to select data from a database. The result is stored in a result table, which is called the result-set.

• A query may retrieve information from selected columns or from all columns in the table. To create a simple SELECT statement, specify the name(s) of the column(s) you need from the table

Syntax of the SQL SELECT Statement:

SELECT column_list
FROM table_name
/* if we want to select all columns from table then, */
SELECT * FROM table_name

The DISTINCT Keyword

The SQL DISTINCT keyword is used in conjunction with SELECT to eliminate all duplicate records and return only unique ones.

SELECT DISTINCT column_name1, column_name2
FROM table_name;

The WHERE Statement

The WHERE clause is used to extract only those records that fulfill a specified criterion. ** The syntax for the WHERE clause:**

SELECT column_list 
FROM table_name
WHERE condition;

PL/SQL