From 5fc143466e789ef451dd361aa3f6d34a85f1ae12 Mon Sep 17 00:00:00 2001
From: Alex Qyoun-ae <4062971+MazterQyou@users.noreply.github.com>
Date: Mon, 19 Sep 2022 19:29:39 +0400
Subject: [PATCH] fix: Correct `INTERVAL + INTERVAL` expression parsing

Recheck this after rebase on commit 57083a0 "Fix interval parsing logic and precedence (#705)", first released in 0.28.0
---
 src/parser.rs             |  2 +-
 tests/sqlparser_common.rs | 53 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/src/parser.rs b/src/parser.rs
index 51a764b9d..5d81c99dc 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -1095,7 +1095,7 @@ impl<'a> Parser<'a> {
 
         // The first token in an interval is a string literal which specifies
         // the duration of the interval.
-        let value = self.parse_expr()?;
+        let value = self.parse_subexpr(Self::PLUS_MINUS_PREC)?;
 
         // Following the string literal is a qualifier which indicates the units
         // of the duration specified in the string literal.
diff --git a/tests/sqlparser_common.rs b/tests/sqlparser_common.rs
index a60f0e3d5..4baf23985 100644
--- a/tests/sqlparser_common.rs
+++ b/tests/sqlparser_common.rs
@@ -2864,6 +2864,59 @@ fn parse_literal_interval() {
     );
 }
 
+#[test]
+fn parse_interval_math() {
+    let sql = "SELECT INTERVAL '1 DAY' + INTERVAL '2 DAY'";
+    let select = verified_only_select(sql);
+    assert_eq!(
+        &Expr::BinaryOp {
+            left: Box::new(Expr::Value(Value::Interval {
+                value: Box::new(Expr::Value(Value::SingleQuotedString("1 DAY".to_string()))),
+                leading_field: None,
+                leading_precision: None,
+                last_field: None,
+                fractional_seconds_precision: None,
+            })),
+            op: BinaryOperator::Plus,
+            right: Box::new(Expr::Value(Value::Interval {
+                value: Box::new(Expr::Value(Value::SingleQuotedString("2 DAY".to_string()))),
+                leading_field: None,
+                leading_precision: None,
+                last_field: None,
+                fractional_seconds_precision: None,
+            })),
+        },
+        expr_from_projection(only(&select.projection)),
+    );
+
+    let sql = "SELECT INTERVAL '1' || ' DAY' + INTERVAL '2 DAY'";
+    let select = verified_only_select(sql);
+    assert_eq!(
+        &Expr::BinaryOp {
+            left: Box::new(Expr::Value(Value::Interval {
+                value: Box::new(Expr::BinaryOp {
+                    left: Box::new(Expr::Value(Value::SingleQuotedString("1".to_string()))),
+                    op: BinaryOperator::StringConcat,
+                    right: Box::new(Expr::Value(Value::SingleQuotedString(" DAY".to_string()))),
+                }),
+                leading_field: None,
+                leading_precision: None,
+                last_field: None,
+                fractional_seconds_precision: None,
+            })),
+            op: BinaryOperator::Plus,
+            right: Box::new(Expr::Value(Value::Interval {
+                value: Box::new(Expr::Value(Value::SingleQuotedString("2 DAY".to_string()))),
+                leading_field: None,
+                leading_precision: None,
+                last_field: None,
+                fractional_seconds_precision: None,
+            })),
+        },
+        expr_from_projection(only(&select.projection)),
+    );
+}
+
 #[test]
 fn parse_at_timezone() {
     let zero = Expr::Value(number("0"));