[GitHub] [arrow-datafusion] andygrove commented on a change in pull request #508: add expr::like and expr::notlike to pruning logic

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

andygrove commented on a change in pull request #508:
URL: https://github.com/apache/arrow-datafusion/pull/508#discussion_r645988035



##########
File path: datafusion/src/physical_optimizer/pruning.rs
##########
@@ -586,8 +587,45 @@ fn build_predicate_expression(
                 .min_column_expr()?
                 .lt_eq(expr_builder.scalar_expr().clone())
         }
+        Operator::Like => {
+            match &**right {
+                // If the literal is a 'starts_with'
+                Expr::Literal(ScalarValue::Utf8(Some(string)))
+                    if !string.starts_with('%') =>
+                {
+                    let scalar_expr =
+                        Expr::Literal(ScalarValue::Utf8(Some(string.replace('%', ""))));
+                    // Behaves like Eq
+                    let min_column_expr = expr_builder.min_column_expr()?;
+                    let max_column_expr = expr_builder.max_column_expr()?;
+                    min_column_expr
+                        .lt_eq(scalar_expr.clone())
+                        .and(scalar_expr.lt_eq(max_column_expr))
+                }
+                _ => unhandled,
+            }
+        }
+        Operator::NotLike => {
+            match &**right {
+                // If the literal is a 'starts_with'
+                Expr::Literal(ScalarValue::Utf8(Some(string)))
+                    if !string.starts_with('%') =>

Review comment:
       We should also consider escaped percent characters in the pattern. Example: `LIKE '100\% %'`




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