我想为一个mysql
创建一个列,该列引用在视图中创建的另一列。
示例:
CREATE VIEW test AS SELECT '30' AS age, age AS person_age;
这不起作用。是否可以重用先前定义的列?
在现实世界中,我先前的age
列是更复杂的计算结果,并且我想在视图的其他列中重用该值。
CREATE VIEW test AS
SELECT age, age AS person_age
FROM (SELECT 30 AS age) t;
CREATE VIEW test AS SELECT '30' AS age, '30' AS person_age;
或使用视图并选择别名
CREATE VIEW test AS SELECT '30' AS age;
CREATE VIEW test2 SELECT age, person_age from test;