Data Analytics

SQL Basics - The Select Statement

SQL is an an abbreviation for Structured Query Language. SQL is made up of very few words to provide simple and efficient way to read and write data from database. The sequence of SELECT clauses is mentioned below. These are all some of the SQL reserved words to retrieve the data.

SELECT
FROM
WHERE
GROUP BY
HAVING
ORDER BY

Note - SQL is not case sensitive

Example Table - Students

student-id	student _name	gender	Attendance	Age	location	Class	section	Contact _no	CGPA
1AB21	Aman	Male	56.23	15	Bangalore	9	A	7654321120	7.9
2AB22	Bhavana	Female	89.65	17	Mangalore	10	B	9876543210	9.3
1AB23	Arjun	Male	56.23	15	Bangalore	9	A	7654325454	9.9
2AB24	Bhuvan	Male	69.65	16	Mysore	10	B	9876543989	8.3
1AB25	Amala	Female	76.23	15	Bangalore	9	A	7657654120	6.9
2AB26	Bhavya	Female	59.65	13	Mandya	8	B	9876567543	9.3

Explanation

CLAUSE	SYNTAX	Example	Explanation
SELECT	SELECT (Col_ name)	SELECT (student_ name )	When specific columns are to be retrieved from a dataset.
FROM	FROM ( Table_ name)	FROM ( Students )	From which table the fields(columns) are to be retrieved.
WHERE	WHERE ( condition for specific rows)	WHERE ( attendance > 80 )	The rows that satisfy the given condition.
GROUP BY	GROUP BY (Col_ name)	GROUP BY ( gender )	Grouping the rows based on a column name.
HAVING	HAVING ( condition for specific groups)	HAVING ( cgpa > 7 )	The groups that satisfy the given condition.
ORDER BY	ORDER BY ( Col_ name)	ORDER BY ( student _ id)	Sorting the output in ascending order.

Output

Bhavana

As she is the only student having cgpa > 7 and attendance > 80

This is the simplest explanation for the sequence of the execution of the select statement in SQL.

Sangeetha Rani S
Dec, 27 2022