From 6396430beb6876745f3364df7734ff0b28ea20c1 Mon Sep 17 00:00:00 2001
From: osipovartem <artemosipov.dev@gmail.com>
Date: Wed, 14 Oct 2026 18:33:09 +0300
Subject: [PATCH] Parse Snowflake ADD COLUMN IF NOT EXISTS

---
 src/parser/mod.rs            |  2 +-
 tests/sqlparser_snowflake.rs | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index 20216d8862..4a4d2e6af3 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -10265,7 +10265,7 @@ impl<'a> Parser<'a> {
                 } else {
                     let column_keyword = self.parse_keyword(Keyword::COLUMN);
 
-                    let if_not_exists = if dialect_of!(self is PostgreSqlDialect | BigQueryDialect | DuckDbDialect | GenericDialect)
+                    let if_not_exists = if dialect_of!(self is PostgreSqlDialect | BigQueryDialect | DuckDbDialect | SnowflakeDialect | GenericDialect)
                     {
                         self.parse_keywords(&[Keyword::IF, Keyword::NOT, Keyword::EXISTS])
                             || if_not_exists
diff --git a/tests/sqlparser_snowflake.rs b/tests/sqlparser_snowflake.rs
index 859ed7bd1e..7f5a42c0ac 100644
--- a/tests/sqlparser_snowflake.rs
+++ b/tests/sqlparser_snowflake.rs
@@ -35,6 +35,26 @@ mod test_utils;
 #[cfg(test)]
 use pretty_assertions::assert_eq;
 
+#[test]
+fn snowflake_alter_table_add_column_if_not_exists() {
+    for sql in [
+        "ALTER TABLE t ADD IF NOT EXISTS value NUMBER",
+        "ALTER TABLE t ADD COLUMN IF NOT EXISTS value NUMBER",
+    ] {
+        let Statement::AlterTable(AlterTable { operations, .. }) = snowflake().verified_stmt(sql)
+        else {
+            panic!("expected ALTER TABLE");
+        };
+        assert!(matches!(
+            operations.as_slice(),
+            [AlterTableOperation::AddColumn {
+                if_not_exists: true,
+                ..
+            }]
+        ));
+    }
+}
+
 #[test]
 fn test_snowflake_create_table() {
     let sql = "CREATE TABLE _my_$table (am00unt number)";