Question

在用SQL创建视图时遇到问题：

问题：从上一个问题中得到答案，并将其放在一个视图中，该视图为表示某人是作者还是编辑者的字段创建一个“类型”列名。

这是我上一个问题的输出：

SELECT 'editor', firstname, lastname
FROM editor
WHERE SUBSTRING(ssn,5,2) = '72'
UNION
SELECT 'author', firstname, lastname
FROM author
WHERE SUBSTRING(ssn,5,2) = '72';

我尝试了以下操作，但它似乎只是将所有“作者”和“编辑”行替换为“类型”。我只需要标题为“类型”

CREATE view as View1
AS
SELECT 'editor', firstname, lastname
FROM editor
WHERE SUBSTRING(ssn,5,2) = '72'
UNION
SELECT 'author', firstname, lastname
FROM author
WHERE SUBSTRING(ssn,5,2) = '72';
SELECT 'editor' as 'type', 'author' as 'type', firstname, lastname
FROM View1;

我正在寻找以下输出：

+--------+-----------+----------+
| type   | firstname | lastname |
+--------+-----------+----------+
| editor | Anne      | Penny    |
+--------+-----------+----------+
| editor | Steve     | Smith    |
+--------+-----------+----------+
| author | Albert    | Singer   |
+--------+-----------+----------+
| author | Serge     | McCluck  |
+--------+-----------+----------+
| author | Robert    | Blue     |
+--------+-----------+----------+

Answer 1

这是您要达到的目标

CREATE VIEW 'my-view' AS
SELECT 'editor' AS Type, firstname AS FName, lastname AS LName
FROM editor
WHERE SUBSTRING(ssn,5,2) = '72'
UNION
SELECT 'author' AS Type, firstname AS FName, lastname AS LName
FROM author
WHERE SUBSTRING(ssn,5,2) = '72';

SQL-创建视图

1 个答案: