Because of the way it is used in databases, Null has some unique characteristics: 1  Expressions involving Null always result in Null. Thus, Null is said to propagate through expressions; if any part of the expression evaluates to Null, the entire expression evaluates to Null.
If the total amount of itemized deductions is more than the standard deduction, a taxpayer can choose to benefit by itemizing. Standard Deduction. Standard deduction, on the other hand, is a particular amount that is deducted to decrease the amount of income chargeable to tax. The deductible amount depends entirely on the filing status of a taxpayer, and increases every year to incorporate the effect of inflation.
The most common itemized deductions include: 1  Deduction for state and local taxes paid. Taxpayers can deduct the entirety of any state and local taxes (including income, property and generalized sales taxes) that they paid for that tax year. 2  Deduction for mortgage interest paid.