The basic form of the SQL SELECT statement is called a mapping or SELECT-FROM-WHERE block.
SELECT <attr list> FROM <table list> WHERE <condition><attr list>is a list of attribute names whose values are to be retrieved by the query<table list>is a list of the relation names required to process the query<condition>is a conditional boolean expression that identifies the tuples to be retrieved by the query. We have access to basic logical operators in the<condition>:=,<,<=,>,>=,<>,!=,AND,OR,NOT,IS NULL, andIS NOT NULL.