我如何在 MySQL 的 ALTER TABLE 中使用 SELECT 语句的结果？

Question

I have a table with some properties. I would like use these properties to create some columns in another table (ALTER TABLE).

The follow SELECT statement result in multiple results:

SELECT property FROM table1 GROUP BY property;

Result example:

• firstName
• lastName
• address
• phone

For each result of select statement above, perform:

ALTER TABLE table2 ADD property boolean null;

How do?

Answer 1

Here is an example for postgres. With little modification you can use it for mysql too.

DO $$
DECLARE row_results record;
BEGIN FOR row_results IN
    SELECT column_name
    FROM information_schema.columns
    WHERE table_schema='public'
        AND table_type='BASE TABLE'
        AND table_name = 'table1'
    LOOP
        EXECUTE format('ALTER TABLE table2 ADD COLUMN %I boolean NULL', row_results.column_name);
    END LOOP;
END$$;