The Equals is a filtering operator that includes only a single attribute value of interest. It can also be used to define the filter condition where two attributes have the same value.
SELECT … WHERE … = …
SELECT metric WHERE attribute = attribute_value
SELECT Salary WHERE Year = 2007
SELECT Revenues WHERE Month = THIS
SELECT Expenses WHERE Quarter = PREVIOUS
SELECT Expenses WHERE Quarter = THIS - 2
SELECT Amount WHERE Date_Ordered = Date_Shipped