T-SQL Fundamentals, 4th Edition

Chapter 5

Table expressions

This chapter focuses on named table expressions. A table expression is an expression—typically a query—that conceptually returns a table result and as such can be nested as an operand of another table expression. Recall that a table in SQL is the counterpart to a relation in relational theory. A table expression is therefore SQL’s counterpart to a relational expression. A relational expression in relational theory is an expression that returns a relation and as such can be nested as an operand of another relational expression. A named table expression is then a table expression that you assign with a name, and interact with like you do with a base table. For example, you can use named table expressions in data-manipulation ...