Difference between Union and Union All in SQL?

Manikandan Murugesan

3y1.5kSQL

2 Answers

Union -> It combines only unique rows. Performance is slower due to this. Union All -> It combines all rows. Performance will be better as it combines all rows.

Tharunkumar Magudeeswaran1y

Union - returns all the values from 2 queries excluding dups
Union All - returna all the values from 2 queries including dups

Umang Pawar3y