Question

我正在使用SQL语句来创建视图，但是我一直遇到语法问题。

我拥有的四张桌子是：

CREATE TABLE "BOOK_ORDER" 
(
  "ID"  INTEGER NOT NULL,
  "Open_Date"   DATE NOT NULL,
  "Close_Date"  DATE,
  "Student_ID"  INTEGER NOT NULL,
  "Book_ID" INTEGER NOT NULL,
CONSTRAINT "PK_ORDER_ID" PRIMARY KEY ("ID")
);
ALTER TABLE "BOOK_ORDER" ADD CONSTRAINT "FK_ORDER_BOOK" FOREIGN KEY ("Book_ID") REFERENCES BOOK ("ID") ON UPDATE CASCADE ON DELETE CASCADE;
ALTER TABLE "BOOK_ORDER" ADD CONSTRAINT "FK_ORDER_STUDENT" FOREIGN KEY ("Student_ID") REFERENCES STUDENTS ("STUDENT_ID") ON UPDATE CASCADE ON DELETE CASCADE;

CREATE TABLE "STUDENTS" 
(
  "STUDENT_ID"  INTEGER NOT NULL,
  "STUDENT_NAME"    VARCHAR(50) NOT NULL,
  "TICKET"  INTEGER NOT NULL,
  "GROUP_ID"    INTEGER NOT NULL,
CONSTRAINT "PK_StUDENTS" PRIMARY KEY ("STUDENT_ID")
);
ALTER TABLE "STUDENTS" ADD CONSTRAINT "FK_GROUP" FOREIGN KEY ("GROUP_ID")     REFERENCES GROUPS ("GROUP_ID") ON UPDATE CASCADE ON DELETE CASCADE;

CREATE TABLE "GROUPS" 
(
  "GROUP_ID"    INTEGER NOT NULL,
  "TITLE"   VARCHAR(50) NOT NULL,
  "CURATOR" VARCHAR(50) NOT NULL,
  "CURATOR_TEL" VARCHAR(20) NOT NULL,
  "FAC_ID"  INTEGER NOT NULL,
CONSTRAINT "PK_GROUP" PRIMARY KEY ("GROUP_ID")
);

CREATE TABLE "BOOK" 
(
  "ID"  INTEGER NOT NULL,
  "CODE"    INTEGER NOT NULL,
  "Name"    VARCHAR(50) NOT NULL,
  "Year"    DATE NOT NULL,
  "Publishing_Office"   VARCHAR(50) NOT NULL,
  "Language"    INTEGER NOT NULL,
CONSTRAINT "PK_BOOK_ID" PRIMARY KEY ("ID")
);

我需要显示有关订单的信息：OpenDate，CloseDate，Student，StudentGroup，Book。

Answer 1

您创建一个语法为CREATE VIEW view_name AS SELECT statement的视图，其中statement是您的常规SELECT语句。

因此，你会这样做：

CREATE VIEW view_name AS
SELECT BOOK_ORDER.id, BOOK_ORDER.OpenDate, BOOK_ORDER.CloseDate, students.student_name, groups.title, book.name
FROM book_order, students, groups, book
WHERE book_order.student_id = students.student_id AND
      book_order.book_id = book.id AND
      students.group_id = groups.group_id

where子句通过在表之间包含重复的值来执行简单连接。我不能保证这会起作用，但这是一个好的开始。

此外，要从视图中获取数据，请从中选择一个以视图作为表名的常规表。

InterBase：如何使用多个表创建视图？

1 个答案: