how-query-engines-work
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andygrove
This is the companion repository for the book How Query Engines Work.
An example under https://howqueryengineswork.com/05-logical-plan.html#math-expressions has a small typo, it should be `name` instead of `"mult"` ``` override fun toField(input: LogicalPlan): Field { return Field("mult", l.toField(input).dataType) } ```
If the sql where statement contains (), an error will occur in SqlParser , eg : " select a from t where (a=1 or b = 2) and c =3...
To cement my understanding of the book, I'm working through it a second time, this time changing the implementation from using Arrow vectors + types (columnar) to row-based data (`Map`)...
https://github.com/andygrove/how-query-engines-work/blob/9c27d475b62e3a4eccec4236e2fe60eb3f13e757/jvm/query-planner/src/main/kotlin/QueryPlanner.kt#L62 
I'm trying to use the engine from Scala. Pretty simple setup. Using example parquet file from testdata folder. Code looks like this: ``` val ctx = new ExecutionContext(Map.empty[String,String].asJava) val pqtSource...
