Questions

The principal quantum number is the property of an electron which determines the energy of electron and the distance of electron from the nucleus of an atom.

India has donated $ 3 lakh for a peacekeeping initiative at the United Nations pipeline for peacekeeping initiative at the UN.

In Britain few of the Canals built during the early days of the Industrial Revolution are now playing an important role in the economy  of the country. Example, Grand Union Canal.

A Subquery or Inner query or a Nested query is a query within another SQL query and embedded within the WHERE clause.

Subqueries are most frequently used with the SELECT statement. The basic syntax is as follows::

SELECT column_name [, column_name ]
FROM table1 [, table2 ]
WHERE column_name OPERATOR
(SELECT column_name [, column_name ]
FROM table1 [, table2 ]
[WHERE])

A subquery is used to return data that will be used in the main query as a condition to further restrict the data to be retrieved.

Subqueries can be used with the SELECT, INSERT, UPDATE, and DELETE statements along with the operators like =, <, >, >=, <=, IN, BETWEEN, etc.

There are a few rules that subqueries must follow −

1. Subqueries must be enclosed within parentheses.

2. A subquery can have only one column in the SELECT clause, unless multiple columns are in the main query for the subquery to compare its selected columns.

3. An ORDER BY command cannot be used in a subquery, although the main query can use an ORDER BY. The GROUP BY command can be used to perform the same function as the ORDER BY in a subquery.

4. Subqueries that return more than one row can only be used with multiple value operators such as the IN operator.

5. The SELECT list cannot include any references to values that evaluate to a BLOB, ARRAY, CLOB, or NCLOB.

6. A subquery cannot be immediately enclosed in a set function.

7. The BETWEEN operator cannot be used with a subquery. However, the BETWEEN operator can be used within the subquery.

Bismillah Khan was associated with Shehnai. He made the Shehnai as the classical musical instrument in his concert in All India Musical Conference, Kolkata in 1937.

A chemical bond in which the electrons are not shared equally due to differences in the electronegativity of the atoms.

The polarity of a covalent bond is measured using its dipole moment.

 Large dipole moment = more polar

 Small dipole moment = more nonpolar.