Assuming I have the following:
swim_names, football_names, soccer_names, swim_age
John, Johnny, Johnson, 5
Mike, Michael, Mike, 2
Jo, Joe, Joey, 7
How can I construct an SQL query such that I can get the following output below:
names, age
John, 5
Johnny, null
Johnson, null
Mike, 2
Michael, null
Mike, null
Jo, 7
Joe, null
Joey, null
Note that:
Try to use UNION ALL
like:
SELECT swim_names as Names, swim_age as age FROM tbl
UNION ALL
SELECT football_names as Names, null as age FROM tbl
UNION ALL
SELECT soccer_names as Names, null as age FROM tbl
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