Re: How to combine 3 databases

[Rick James]

mysqldump generated the dumps, I hope?

Were the dumps taken from different "databases"? (I am not talking about "servers" or "tables".) If not, do the dumps have CREATE DATABASE and USE statements? If so, remove them so that you can insert the _tables_ into different _databases_ when you reload.

Then do the load.

Then do whatever SQL is needed to
ALTER TABLE xx DROP COLUMN yy; -- drop a table
CREATE TABLE new SELECT ... FROM old WHERE NOT (...); -- drop selected rows
etc.

Sorry, but your question was too vague for me to be more specific. There is no magic wand.