[5.6] Add helpers for subquery join clauses#23818

Merged

taylorotwell merged 2 commits intolaravel:5.6from staudenmeir:5.6

Apr 17, 2018

+94

Commits on Apr 5, 2018

Add joinSub(), leftJoinSub(), rightJoinSub() to query builder
staudenmeir
committed

Commits on Apr 7, 2018

Add joinSub() test with multiple subqueries
staudenmeir
committed