What is the difference between SELECT * and SELECT 1?

What does * mean in SELECT statement?

An asterisk (" * ") can be used to specify that the query should return all columns of the queried tables. SELECT is the most complex statement in SQL, with optional keywords and clauses that include: The FROM clause, which indicates the table(s) to retrieve data from.

What is the difference between SELECT and SELECT *?

SELECT ALL means ALL rows, i.e including duplicate rows. (The opposite is SELECT DISTINCT , where duplicate rows are removed.) ALL is the default, and most people write just SELECT instead of SELECT ALL . SELECT * means all columns.

What SELECT 1 means?

The statement 'select 1' from any table name means that it returns only 1. For example, If any table has 4 records then it will return 1 four times.

What is the difference between count 1 and count (*)?

The difference is simple: COUNT(*) counts the number of rows produced by the query, whereas COUNT(1) counts the number of 1 values. Note that when you include a literal such as a number or a string in a query, this literal is "appended" or attached to every row that is produced by the FROM clause.