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SQL

SQL Clause

Where Clause is used to extract only those records that satisfied the given condition.

To retrieve the only specific record

To delete the only specific record

To update only specific record

Syntax:

SELECT column1, column 2, ... column n
FROM table_name
WHERE [conditions]

Example: SELECT * from student WHERE marks >70;

Operators in THE WHERE CLAUSE:

OperatorDescription
=EQUAL
>GREATER THAN
<LESS THAN
>=GREATER THAN OR EQUAL
<=LESS THAN OR EQUAL
<>NOT EQUAL TO
AND CLAUSE:

It is used to combine two or more than two conditions together.

Syntax
SELECT columns FROM table_name
WHERE condition1 AND condition 2;
Example
SELECT * from student
WHERE marks>75 and branch='BTech';
OR CLAUSE:

OR clause is used to combine two or more than two conditions together, In this case, you need at least one condition to be true then only it will return the result.

Syntax
SELECT columns FROM table_name
WHERE condition1 or condition 2;
Example
SELECT * from Customers
WHERE Country='India'AND City='kakinada';
NOT Operator:

The NOT operator retrieves records if the condition(s) is NOT TRUE.

Syntax
SELECT column1, column2, ... FROM table_name
WHERE NOT condition;
Example
SELECT * from student
WHERE NOT Country='USA';
Like Operator:

Like Operator is used in a WHERE clause to search for a specified pattern in a column.

suppose you want to search those students' records whose names start with ‘A ‘ alphabet.

There are two wildcards used in Like Operator.

The percent sign (%) represents zero, one, or multiple characters.

The underscore sign (_) represents one, single character .

Syntax
SELECT column1, column2, ... FROM table_name (
WHERE columnNLIKE pattern;
Example
SELECT * from student
SELECT * FROM student WHERE student_nameLIKE 'a%';
LIKE OperatorDescription
WHERE student_name LIKE ‘a%’Find any values that start with “a”
WHERE student_name LIKE ‘%a’Find any values that ends with “a”
WHERE student_name LIKE ‘%or%’Find any values that have “or” in any position
WHERE student_name LIKE ‘_r%’Find any values that have “r” in the second position
WHERE student_name LIKE ‘a_%’Find any values that start with “a” and at least 2 characters in length
WHERE student_name LIKE ‘a__%’Find any values that start with “a” and at least 3 characters in length
WHERE student_name LIKE ‘a%o’Find any values that start with “a” and ends “o”
Between Operator:

BETWEEN returns values that fall within a given range.

BETWEEN is a shorthand for >= AND <=.

BETWEEN operator is inclusive : begin and end values are included.

The underscore sign (_) represents one, single character .

Syntax
SELECT column_name(s) FROM table_name
WHERE column_name BETWEEN value1 AND value2;
Example
SELECT * from student
WHERE marksBETWEEN 60 AND 75;
IN Operator:

The IN operator allows you to specify multiple values in a WHERE clause.

The IN operator is a shorthand for multiple OR conditions.

Syntax
SELECT column_name(s) FROM table_name (
WHERE column_name IN (value1, value2, ...);
OR SELECT column_name(s) FROM table_name (
WHERE column_name IN (SELECT STATEMENT);
Example
SELECT * from student
WHERE Country IN('india','usa','china');
 SELECT * from student
WHERE Country IN(SELECT Country FROM employee);