From 5d089e0c42052f7aa9622bfd6165e2c358c823b9 Mon Sep 17 00:00:00 2001
From: prql-bot <107324867+prql-bot@users.noreply.github.com>
Date: Wed, 25 Mar 2026 09:10:36 +0000
Subject: [PATCH] fix: BETWEEN optimization now triggers by comparing expr
 kind, not span

The `try_into_between` function compared full `rq::Expr` values (including
`span`) to detect `a >= low AND a <= high` patterns. Since the two references
to the same column originate from different source positions, their spans
differ, causing the equality check to always fail. Compare only `kind` instead.

Closes #5737

Co-Authored-By: Claude <noreply@anthropic.com>
---
 prqlc/prqlc/src/sql/gen_expr.rs      |  2 +-
 prqlc/prqlc/tests/integration/sql.rs | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/prqlc/prqlc/src/sql/gen_expr.rs b/prqlc/prqlc/src/sql/gen_expr.rs
index 2fe0786b16f3..973647600a0c 100644
--- a/prqlc/prqlc/src/sql/gen_expr.rs
+++ b/prqlc/prqlc/src/sql/gen_expr.rs
@@ -432,7 +432,7 @@ fn try_into_between(expr: rq::Expr, ctx: &mut Context) -> Result<Option<sql_ast:
 
                     // We need for the values on each arm to be the same; e.g. x
                     // > 3 and x < 5
-                    if a_l == b_l {
+                    if a_l.kind == b_l.kind {
                         return Ok(Some(sql_ast::Expr::Between {
                             expr: Box::new(
                                 translate_operand(a_l, true, 0, Associativity::Both, ctx)?
diff --git a/prqlc/prqlc/tests/integration/sql.rs b/prqlc/prqlc/tests/integration/sql.rs
index f8dd1d03b042..2c117d3ad585 100644
--- a/prqlc/prqlc/tests/integration/sql.rs
+++ b/prqlc/prqlc/tests/integration/sql.rs
@@ -1575,6 +1575,21 @@ fn test_ranges() {
     ");
 }
 
+#[test]
+fn test_between_from_comparison() {
+    assert_snapshot!((compile(r###"
+    from t
+    filter (a >= 5 && a <= 10)
+    "###).unwrap()), @r"
+    SELECT
+      *
+    FROM
+      t
+    WHERE
+      a BETWEEN 5 AND 10
+    ");
+}
+
 #[test]
 fn test_in_values_01() {
     assert_snapshot!((compile(r#"