Tutor profile: Richa J.
Subject: SQL Programming
List some of the ways you can performance tune an SQL Query
In order to performance tune an SQL Query evaluate the following and optimize the query if needed to incorporate the below guidelines. 1) Use the driving table as the one that returns minimum number of rows . This way there will be less probes needed to the subsequent tables. 2) Use indexes on columns which are used in the join condition. Using an index avoid full table scan and returns the results 10X times faster 3) Use Exists where possible instead of IN 4) Use NOT EXISTS where possible instead on NOT IN 5) Avoid using NOT NULL or OR operators as they do not allow the use of indexes 6) Create function based indexes on columns what use inbuilt functions in the join condition. There can be other solutions based on the specific scenario but these common rules help tune most of the queries and improve performance.
Subject: Basic Math
Expand (a+b)^2 Expand (a+b)^3
1) (a+b)^2 = a2 + 2ab + b2 2) (a + b)^3 = a3 + 3a2b + 3ab2 + b3
Subject: Basic Chemistry
What is an Atom
An atom is the basic building block of any matter that we see around us. Atoms join together to form molecules and practically everything we see is made up of molecules as building blocks. Furthermore , an atom is made up of 3 essential particles Proton : A proton carries a positive charge and is found clustered together with the neutron in the central part of the atom called the nucleus Neutron : A neutron does not carry any electrical charge and is found clustered together with the proton in the central part of the atom called the nucleus Electron : An electron carries a negative electrical charge and it orbits around the nucleus. An atom has the same number of electron as there are protons.
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