Matthew 21:12 "he overturned the tables of the money-changers and the seats of those who sold pigeons". ESV This is repeated in Mark 11:15.
John 2:16 "And he told those who sold the pigeons, "Take these things away..".
A. I think in John 2:16 Jesus treats the pigeon sellers relatively gently. NIV "Get these out of here" [in an orderly way? Before they fly around wildly? Perhaps].
However, does the overturning of the seats in Matthew suggest something more violent and emphatic? Instead of taking the birds out of the building in an fairly orderly way they would have been scrabbling around trying to rescue their belongings.
This would suggest a first cleansing towards the beginning of His ministry in John, and a second more aggressive cleansing in Matthew towards the end of His ministry.
B. Jesus making a comment on temple sacrifice, and in particular those selling the cheapest animals which might be the only ones the poor could afford, are issues mentioned in other questions on this site, or various commentaries. Here I want to focus on how those who sold pigeons are treated.
In A. is there enough evidence to prove there were two cleansings as the second one was more violent and emphatic?
My NIV Study Bible footnotes say that there is uncertainty as to whether or not there were one or two cleansings.