视图中的最大列数

Question

There is a (complex) maximum number of columns in a table in mySQL.

But what about a maximum number of columns in a view?

I mean, a view might be a join of numerous tables. Will there be a maximum of the total number of columns?

Thanks in advance.

Answer 1

According to the MySQL 5.7 reference manual , there is a maximum of 4096 columns per table. I am not sure if this is also the case for queries though I would assume so and I also don't think that you would practically every have a database table or search query with over that amount.

Answer 2

By way of example, a questionnaire table might look like this:

questionnaire_id, question_no, question
               1            1  What is your name?
               1            2  Where do you live?
               1            3  What is your favourite colour?
               2            1  What is the capital of France?
               2            2  Who wrote Beethoven's Fifth?
               2            3  When was the Great Fire of London?

So, there we have two questionnaires (of potentially unlimited length) occupying exactly 3 columns in a table.

Any remaining 'user-experience' issues would properly be handled in application code.