From 349936285bc12fbb39f1c1ecfae6480f86c9ae71 Mon Sep 17 00:00:00 2001
From: Phillip Cloud <417981+cpcloud@users.noreply.github.com>
Date: Sun, 24 Sep 2023 06:10:21 -0400
Subject: [PATCH] feat(clickhouse): add isnan and startswith renamings

---
 sqlglot/dialects/clickhouse.py    |  2 ++
 tests/dialects/test_clickhouse.py | 12 ++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/sqlglot/dialects/clickhouse.py b/sqlglot/dialects/clickhouse.py
index 744608101b..14f953b614 100644
--- a/sqlglot/dialects/clickhouse.py
+++ b/sqlglot/dialects/clickhouse.py
@@ -359,12 +359,14 @@ class Generator(generator.Generator):
                 "DATE_DIFF", exp.Literal.string(e.text("unit") or "day"), e.expression, e.this
             ),
             exp.Final: lambda self, e: f"{self.sql(e, 'this')} FINAL",
+            exp.IsNan: rename_func("isNaN"),
             exp.Map: lambda self, e: _lower_func(var_map_sql(self, e)),
             exp.PartitionedByProperty: lambda self, e: f"PARTITION BY {self.sql(e, 'this')}",
             exp.Pivot: no_pivot_sql,
             exp.Quantile: lambda self, e: self.func("quantile", e.args.get("quantile"))
             + f"({self.sql(e, 'this')})",
             exp.RegexpLike: lambda self, e: f"match({self.format_args(e.this, e.expression)})",
+            exp.StartsWith: rename_func("startsWith"),
             exp.StrPosition: lambda self, e: f"position({self.format_args(e.this, e.args.get('substr'), e.args.get('position'))})",
             exp.VarMap: lambda self, e: _lower_func(var_map_sql(self, e)),
             exp.Xor: lambda self, e: self.func("xor", e.this, e.expression, *e.expressions),
diff --git a/tests/dialects/test_clickhouse.py b/tests/dialects/test_clickhouse.py
index 40a270ed7e..da07eb76ef 100644
--- a/tests/dialects/test_clickhouse.py
+++ b/tests/dialects/test_clickhouse.py
@@ -225,6 +225,18 @@ def test_clickhouse(self):
             "SELECT s, arr_external FROM arrays_test ARRAY JOIN [1, 2, 3] AS arr_external"
         )
 
+        self.validate_identity("SELECT isNaN(x)")
+        self.validate_all(
+            "SELECT IS_NAN(x), ISNAN(x)",
+            write={"clickhouse": "SELECT isNaN(x), isNaN(x)"},
+        )
+
+        self.validate_identity("SELECT startsWith('a', 'b')")
+        self.validate_all(
+            "SELECT STARTS_WITH('a', 'b'), STARTSWITH('a', 'b')",
+            write={"clickhouse": "SELECT startsWith('a', 'b'), startsWith('a', 'b')"},
+        )
+
     def test_cte(self):
         self.validate_identity("WITH 'x' AS foo SELECT foo")
         self.validate_identity("WITH SUM(bytes) AS foo SELECT foo FROM system.parts")