SQLを使い始めたとき、 多くのプログラマが例外なく難儀するのが、 SQLで制御構造をうまく書けないことです。ここで言う制御構造とは、 平たく言えば条件分岐とループです。といっても別に、 SQLに制御構造を書くための機能が備わっていないとか、 貧弱 ...

Abstract: In this paper, we present a translator from a relevant subset of SQL into relational algebra. The translation is syntax-directed, with translation rules associated with grammar productions; ...

Note: This example uses a Version 6 view descriptor with the Pass-Through Facility to access DBMS data. Beginning in Version 7, you can associate a libref directly with your DBMS data and use the ...

operand is one of the following: constant is a number or a quoted character string (or other special notation) that indicates a fixed value. Constants are also called literals. Constants are described ...

SQL is the de facto query language used to interact with databases. Since SQL is declarative, users express the intended result of their query rather than the concrete procedural steps to produce the ...