What types of joins are commonly used

join_frequencies.sh

# install tool for cloning github repositories
python -m pip install git+https://github.com/sellisd/gitrepodb.git

# Clone top 20 (based on star-rating) SQL repositories
gitrepodb init
gitrepodb query --project SQL --query 'language:SQL,sort:stars-desc:archived=False' --head 20
gitrepodb add --basepath ~/data/
gitrepodb download --project SQL
find ~/data/ -name *.sql -exec grep 'JOIN' {} \;> join_types.dat

# Extract relevant lines
find ./ -name *.sql -exec grep 'JOIN' {} \;> join_types.dat

# Roughly count different types of joins:
# $ grep JOIN join_types.dat |wc -l
# 2744
# $ grep INNER join_types.dat |wc -l
# 172
# $ grep LEFT join_types.dat |wc -l
# 142
# $ grep OUTER join_types.dat |wc -l
# 63
# $ $ grep RIGHT join_types.dat |wc -l
# 4