[GitHub] [arrow] seddonm1 commented on a change in pull request #9038: ARROW-10356: [Rust][DataFusion] Add support for is_in (WIP)

[GitBox <gi...@apache.org>]

seddonm1 commented on a change in pull request #9038:
URL: https://github.com/apache/arrow/pull/9038#discussion_r550807996



##########
File path: rust/datafusion/src/logical_plan/expr.rs
##########
@@ -158,6 +158,15 @@ pub enum Expr {
         /// List of expressions to feed to the functions as arguments
         args: Vec<Expr>,
     },
+    /// Returns whether the list contains the expr value.
+    InList {
+        /// The value to compare
+        expr: Box<Expr>,
+        /// The low end of the range
+        list: Vec<Expr>,
+        /// Whether the expression is negated
+        negated: bool,

Review comment:
       Thanks for the comments. I have done some testing with Postgres 13.1 and found that it does not appear to make a difference. These are all equivalent and return `NULL`.
   
   ```sql
   SELECT NOT NULL IN ('a');
   SELECT NULL NOT IN ('a');
   SELECT NOT 'a' IN (NULL);
   SELECT 'a' NOT IN (NULL);
   ```




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