JOINs

The JOIN is used to combine rows from two or more tables. SQL Inner Join :- Select all rows from tables for the match between the columns in tables. Same as JOIN Syntax :- SELECT column FROM table1 INNER JOIN table2 on table1.column =...

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UNION Operator

Combines the result of two or more select statement. Each Select Statement must have same number of columns and columns must have same data types. Columns should also be in same order. Syntax :- [ Removes the duplicate Values ] SELECT...

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FOREIGN KEY

A FOREIGN KEY in one table points to PRIMARY KEY in another table. A foreign key can have a different name than the primary key it comes from. The primary key used by a foreign key is also known as a parent key. The table where the primary...

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ALTER TABLE

This command is used to Add/Change/Modify/Drop existing structure of the table. ADD Column Enable/Disable Constraints Change Column Modify Column Drop Column ADD Column :- When a new column is to be added to the table structure without constraints. Syntax :- ALTER TABLE table_name ADD COLUMN column_name datatype (size); Example:- ALTER TABLE...

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SQL The Complete Reference, 3rd Edition Paperback – 1 Jul 2017 by James Groff (Author), Paul Weinberg (Author), Andy Oppel (Author)

SQL The Complete Reference, 3rd Edition Get comprehensive coverage of every aspect of SQL from three leading industry experts. Revised with coverage of the latest RDBMS software versions, this one-stop guide explains how to build,...

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Auto Increment

Auto increment is used to  generate an unique, when a new record is inserted into a table. If use a auto increment than increase by 1.  In table sequence is increment automatically. Auto increment ignore null value. Syntax :- CREATE...

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PRIMARY KEY

The PRIMARY KEY constraints uniquely identifies each record in a database table. Primary keys must contain UNIQUE values. A primary key column cannot contain NULL values. Most a tables should have a primary key, and each table can have only...

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UNIQUE KEY

The UNIQUE constraint uniquely identifies each record in a database table. There can be many UNIQUE constraints per table.  A Unique key column can contain NULL values. Syntax :-    CREATE TABLE student    (    ...

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ORDER BY

This is used to sort the record. ASC - It sorts in ascending order (by default). DESC - It sorts in descending order. 1. Sorts in descending order Syntax :-    SELECT * FROM table_name    ORDER BY column_name DESC; Example...

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LIKE Operator

The LIKE operator is used to search for a specified pattern in a column. Syntax :-     SELECT * FROM table_name     WHERE column_name LIKE 'pattern'; Example :-     SELECT * FROM new_tab    ...

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BETWEEN Number operator

The BETWEEN operator selects values within a range. The values can be numbers, text, or dates. 1. Between Number Syntax :-    SELECT * FROM table_name   WHERE column_name BETWEEN value1 and value2; Example :-   SELECT...

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IN Operator

The IN operator allows you to specify multiple values in a WHERE clause. Syntax :-    SELECT * FROM table_name    WHERE column_name IN ('value1' , 'value2' , ......); Example :-   SELECT * FROM table_name  ...

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OR Operator

The OR operator displays a record if either the first condition OR the second condition is true. Syntax :-   SELECT * FROM table_name   WHERE column_name = 'value'    OR column = 'value'; Example :-    SELECT...

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AND Operator

The AND operator display a records if both the first condition AND the second condition are true. Syntax :-      SELECT * FROM table_name     WHERE column_name = 'value'     AND column = 'value'; Ex:-  SELECT...

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SQL Statements and Rules

SQL command or statement is a special kind of sentence that contains clauses and all end with a semicolon(;) just as a sequence ends with a period. SQL statements are divided into four sub language: (i) Data Definition Language (DDL):- It is used to define the structure of tables in the database.It contains the necessary statement to CREATE , RENAME...

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