MySQL 5.6中生成列的替代方法是什么 [英] What is the alternative for generated column in MySQL 5.6

问题描述

我有一个MySQL alter语句

I have a MySQL alter statement

ALTER TABLE `employee`
ADD `employee_name_generator` CHAR(20) GENERATED ALWAYS AS
    (COALESCE(concat(`employee_name`), '^')) VIRTUAL;

这是在唯一约束中添加employee_name_generator所必需的.在MySQL 5.7及更高版本中，此方法运行良好.但是我需要的环境是MySQL 5.6. MySQL 5.6是否有替代选择?

This is needed for adding employee_name_generator in a unique constraint. This works fine in MySQL 5.7 onwards. But the environment where I need this has MySQL 5.6. Is there an alternative for MySQL 5.6?

推荐答案

如果您的早期版本的MySQL不支持生成的列，那么您必须在查询时计算该列.一种选择是视图:

If your earlier version of MySQL does not support generated columns, then you'll have to compute that column at the time you query. One option would be a view:

CREATE VIEW yourView AS (
    SELECT *, COALESCE(CONCAT(employee_name, '^')) AS employee_name_generator
    FROM employee
)

MySQL不支持(直接)实例化视图.因此，如果您确实需要实例化视图的行为，则必须执行类似的操作，例如，在我上面给出的视图中使用选择逻辑来创建临时表.

MySQL does not support materialized views (directly). So, if you really needed the behavior of a materialized view, you would have to do something like create a temporary table using the select logic in the view I gave above.

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