Chore(snowflake): Adding type annotation tests for Snowflake's STDDEV / STDDEV_SAMP, STDDEV_POP (#6641)

* Add STDDEV/STDDEV_POP/STDDEV_SAMP support with Snowflake mapping STDDEV → STDDEV_SAMP, window function arg_types, and corresponding tests.

* added partition tests

* fixed arguments

* removed redundant definition

* made STDDEV and STDDEV_SAMP parse as the same

Author: fivetran-kwoodbeck

sqlglot/dialects/snowflake.py

@@ -804,6 +804,7 @@ class Parser(parser.Parser):
             "SHA2_BINARY": exp.SHA2Digest.from_arg_list,
             "SHA2_HEX": exp.SHA2.from_arg_list,
             "SQUARE": lambda args: exp.Pow(this=seq_get(args, 0), expression=exp.Literal.number(2)),
+            "STDDEV_SAMP": exp.Stddev.from_arg_list,
             "STRTOK": _build_strtok,
             "SYSDATE": lambda args: exp.CurrentTimestamp(this=seq_get(args, 0), sysdate=True),
             "TABLE": lambda args: exp.TableFromRows(this=seq_get(args, 0)),

tests/dialects/test_snowflake.py

@@ -474,6 +474,14 @@ def test_snowflake(self):
         self.validate_identity("WEEKOFYEAR(tstamp)", "WEEK(tstamp)")
         self.validate_identity("SELECT QUARTER(CURRENT_TIMESTAMP())")
         self.validate_identity("SELECT SUM(amount) FROM mytable GROUP BY ALL")
+        self.validate_identity("SELECT STDDEV(x)")
+        self.validate_identity("SELECT STDDEV(x) OVER (PARTITION BY 1)")
+        self.validate_identity("SELECT STDDEV_POP(x)")
+        self.validate_identity("SELECT STDDEV_POP(x) OVER (PARTITION BY 1)")
+        self.validate_identity("SELECT STDDEV_SAMP(x)", "SELECT STDDEV(x)")
+        self.validate_identity(
+            "SELECT STDDEV_SAMP(x) OVER (PARTITION BY 1)", "SELECT STDDEV(x) OVER (PARTITION BY 1)"
+        )
         self.validate_identity("WITH x AS (SELECT 1 AS foo) SELECT foo FROM IDENTIFIER('x')")
         self.validate_identity("WITH x AS (SELECT 1 AS foo) SELECT IDENTIFIER('foo') FROM x")
         self.validate_identity("INITCAP('iqamqinterestedqinqthisqtopic', 'q')")

tests/fixtures/optimizer/annotate_functions.sql

@@ -4092,6 +4092,30 @@ BOOLEAN;
 SEARCH_IP(col, '192.168.0.0');
 BOOLEAN;
 
+# dialect: snowflake
+STDDEV(tbl.double_col);
+DOUBLE;
+
+# dialect: snowflake
+STDDEV(tbl.double_col) OVER (PARTITION BY 1);
+DOUBLE;
+
+# dialect: snowflake
+STDDEV_POP(tbl.double_col);
+DOUBLE;
+
+# dialect: snowflake
+STDDEV_POP(tbl.double_col) OVER (PARTITION BY 1);
+DOUBLE;
+
+# dialect: snowflake
+STDDEV_SAMP(tbl.double_col);
+DOUBLE;
+
+# dialect: snowflake
+STDDEV_SAMP(tbl.double_col) OVER (PARTITION BY 1);
+DOUBLE;
+
 # dialect: snowflake
 STRTOK_TO_ARRAY('a,b,c', ',');
 ARRAY;