Refactor(clickhouse): clean up chr, lag, lead generation

Author: georgesittas

sqlglot/dialects/clickhouse.py

@@ -887,13 +887,10 @@ class Generator(generator.Generator):
             exp.Stddev: rename_func("stddevSamp"),
             exp.Chr: lambda self, e: self.func("char", e.this),
             exp.Lag: lambda self, e: self.func(
-                "lagInFrame", e.this, e.args["offset"], e.args["default"]
+                "lagInFrame", e.this, e.args.get("offset"), e.args.get("default")
             ),
             exp.Lead: lambda self, e: self.func(
-                "leadInFrame",
-                e.this,
-                e.args["offset"],
-                e.args["default"],
+                "leadInFrame", e.this, e.args.get("offset"), e.args.get("default")
             ),
         }
 

tests/dialects/test_clickhouse.py

@@ -159,6 +159,27 @@ def test_clickhouse(self):
             "SELECT SUM(1) AS impressions FROM (SELECT ['Istanbul', 'Berlin', 'Bobruisk'] AS cities) WHERE arrayJoin(cities) IN ('Istanbul', 'Berlin')",
         )
 
+        self.validate_all(
+            "char(67) || char(65) || char(84)",
+            read={
+                "clickhouse": "char(67) || char(65) || char(84)",
+                "oracle": "chr(67) || chr(65) || chr(84)",
+            },
+        )
+        self.validate_all(
+            "SELECT lagInFrame(salary, 1, 0) OVER (ORDER BY hire_date) AS prev_sal FROM employees",
+            read={
+                "clickhouse": "SELECT lagInFrame(salary, 1, 0) OVER (ORDER BY hire_date) AS prev_sal FROM employees",
+                "oracle": "SELECT LAG(salary, 1, 0) OVER (ORDER BY hire_date) AS prev_sal FROM employees",
+            },
+        )
+        self.validate_all(
+            "SELECT leadInFrame(salary, 1, 0) OVER (ORDER BY hire_date) AS prev_sal FROM employees",
+            read={
+                "clickhouse": "SELECT leadInFrame(salary, 1, 0) OVER (ORDER BY hire_date) AS prev_sal FROM employees",
+                "oracle": "SELECT LEAD(salary, 1, 0) OVER (ORDER BY hire_date) AS prev_sal FROM employees",
+            },
+        )
         self.validate_all(
             "SELECT CAST(STR_TO_DATE('05 12 2000', '%d %m %Y') AS DATE)",
             read={

tests/test_transpile.py

@@ -3,7 +3,6 @@
 from unittest import mock
 
 from sqlglot import parse_one, transpile
-from sqlglot.dialects import Oracle, ClickHouse
 from sqlglot.errors import ErrorLevel, ParseError, UnsupportedError
 from sqlglot.helper import logger as helper_logger
 from sqlglot.parser import logger as parser_logger
@@ -22,26 +21,6 @@ class TestTranspile(unittest.TestCase):
     def validate(self, sql, target, **kwargs):
         self.assertEqual(transpile(sql, **kwargs)[0], target)
 
-    def test_functions(self):
-        self.validate(
-            'SELECT CHR(67)||CHR(65)||CHR(84) "Dog" FROM DUAL',
-            'SELECT char(67) || char(65) || char(84) AS "Dog" FROM DUAL',
-            read=Oracle,
-            write=ClickHouse,
-        )
-        self.validate(
-            "SELECT LAG(salary, 1, 0) OVER (ORDER BY hire_date) AS prev_sal FROM employees",
-            "SELECT lagInFrame(salary, 1, 0) OVER (ORDER BY hire_date) AS prev_sal FROM employees",
-            read=Oracle,
-            write=ClickHouse,
-        )
-        self.validate(
-            "SELECT LEAD(salary, 1, 0) OVER (ORDER BY hire_date) AS prev_sal FROM employees",
-            "SELECT leadInFrame(salary, 1, 0) OVER (ORDER BY hire_date) AS prev_sal FROM employees",
-            read=Oracle,
-            write=ClickHouse,
-        )
-
     def test_weird_chars(self):
         self.assertEqual(transpile("0Êß")[0], "0 AS Êß")