about the function set() in the Update query.

[Xantolee]

now the set() function could set col as a value. However, we have the requirement to set a col as another col in the same table. The current set() function could not do this. Could you add this into set()?

[arthurhsu]

We do not support subqueries and do not have plans to do so.

[freshp86]

See #141