Use of in Function
• Whenever a field needs to be tested against a list of valid values it is recommended to use the IN function and not compare the field against each and every value.
• Wrong way:
◦ Select ...
◦ From ...
◦ Where ... (A = '10' or A='20' or A='30')
• Right way:
◦ Select ...
◦ From ...
◦ Where ... A IN ('10','20','30')