具有两个不同列的 SQL 合并表

Question

I have two tables that look like this:

table1:

table2:

and I'd like to merge them, to create a table with a header like this:

variablenname | mean | stddev | ms_form | dependent | fvalue | probf

The first nine rows should be the first table with empty values in the last 3 columns followed by the three rows from the second table with empty values in the first 4 columns. I'm sorry I can't post pictures or a third link, but my reputation is too low. I hope it's understandable.

I tried to create a new table and select everything from both with union but that didn't work. Can anybody help me?

Thanks!

Answer 1

This is how I would like the final table to look like:

Answer 2

You can use ALTER to add the last 3 columns to table 1. From there, INSERT table 2 onto table 1. So something like this.

ALTER table1 ADD dependent varchar(16)
ALTER table1 ADD favalue varchar(16)
ALTER table1 ADD probf varchar(16)

INSERT INTO table1(dependent, fvalue, probf)
  SELECT * FROM table2

Answer 3

You can use a combination of joins and unions

LEFT JOIN the two tables in first query on fields that won't have a match then UNION the second query with a RIGHT JOIN of the same tables.

The LEFT JOIN will only show results from the first table, then the RIGHT JOIN will only show results from the second

Something Like:

SELECT * FROM table1 as t1 
LEFT JOIN table1 as t2 on t1.variablenname = t2.fValue 
UNION 
SELECT * FROM table1 as t1 
RIGHT JOIN table1 as t2 on t1.variablenname = t2.fValue;