Data Update using Java vs Database

Question

I want to find out the best approach to Data Updates between Java and MonogoDB.

Lets say, I have two database tables Table_A(have more than 100K Rows) and Table_B and I want to copy data of Table_A into Table_B. But the catch is that I want to copy only few Columns of Table_A into Table_B. I have two solutions to do this 1) One is java take data from Table_A iterate all the rows and copy into Table_B. 2) A simple Query of Database, which will copy data from Table_A to Table_B as per the chosen column.

I want to know which one will be an efficient approach in term time consumption and Memory Consumption.

Answer 1

Obviously from performance point of view do it directly on using SQL query, On SQL we have so many inbuilt function to manipulate any column value; As well as you can choose few column from TABLE_2 to TABLE_1.