A Look at Three Join Methods: Hash, Merge, Nested Loops

In this episode of Ask TOM Office Hours, we looked at the three join methods:

* Hash joins
* Merge joins
* Nested loops

We covered how these work and their relative strengths and weaknesses

Highlights include:

02:35 - Example queries for unindexed joins
10:30 - How a hash join works
13:40 - How a merge join works
21:05 - How a nested loop works
28:35 - Example joins in top-N queries
45:15 - How indexes affect joins
49:00 - Example joins wheen filtering one table
52:10 - How adaptive plans work
53:30 - Summary; time complexity of the joins, how indexes affect them, and their optimal use case

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