refactor(exasol)!: map date/timestamp TRUNC to DATE_TRUNC (#6328)

* chore(exasol): implementing date trunc, trunc relating to date and timestamp trunc to exasol date_trunc

* chore(exasol): refactored implmentation using is_string to check if expression is a string and adding more test

Author: nnamdi16

sqlglot/dialects/exasol.py

@@ -12,7 +12,6 @@
     rename_func,
     strposition_sql,
     timestrtotime_sql,
-    unit_to_str,
     timestamptrunc_sql,
     build_date_delta,
 )
@@ -107,6 +106,27 @@ def prefix_local(node):
     return expression
 
 
+def _trunc_sql(self: Exasol.Generator, kind: str, expression: exp.DateTrunc) -> str:
+    unit = expression.text("unit")
+    node = expression.this.this if isinstance(expression.this, exp.Cast) else expression.this
+    expr_sql = self.sql(node)
+    if isinstance(node, exp.Literal) and node.is_string:
+        expr_sql = (
+            f"{kind} '{node.this.replace('T', ' ')}'"
+            if kind == "TIMESTAMP"
+            else f"DATE '{node.this}'"
+        )
+    return f"DATE_TRUNC('{unit}', {expr_sql})"
+
+
+def _date_trunc_sql(self: Exasol.Generator, expression: exp.DateTrunc) -> str:
+    return _trunc_sql(self, "DATE", expression)
+
+
+def _timestamp_trunc_sql(self: Exasol.Generator, expression: exp.DateTrunc) -> str:
+    return _trunc_sql(self, "TIMESTAMP", expression)
+
+
 DATE_UNITS = {"DAY", "WEEK", "MONTH", "YEAR", "HOUR", "MINUTE", "SECOND"}
 
 
@@ -308,7 +328,7 @@ def datatype_sql(self, expression: exp.DataType) -> str:
             # https://docs.exasol.com/db/latest/sql_references/functions/alphabeticallistfunctions/div.htm#DIV
             exp.IntDiv: rename_func("DIV"),
             exp.TsOrDsDiff: _date_diff_sql,
-            exp.DateTrunc: lambda self, e: self.func("TRUNC", e.this, unit_to_str(e)),
+            exp.DateTrunc: _date_trunc_sql,
             exp.DayOfWeek: lambda self, e: f"CAST(TO_CHAR({self.sql(e, 'this')}, 'D') AS INTEGER)",
             exp.DatetimeTrunc: timestamptrunc_sql(),
             exp.GroupConcat: lambda self, e: groupconcat_sql(
@@ -338,7 +358,7 @@ def datatype_sql(self, expression: exp.DataType) -> str:
             exp.TsOrDsToDate: lambda self, e: self.func("TO_DATE", e.this, self.format_time(e)),
             exp.TimeToStr: lambda self, e: self.func("TO_CHAR", e.this, self.format_time(e)),
             exp.TimeStrToTime: timestrtotime_sql,
-            exp.TimestampTrunc: timestamptrunc_sql(),
+            exp.TimestampTrunc: _timestamp_trunc_sql,
             exp.StrToTime: lambda self, e: self.func("TO_DATE", e.this, self.format_time(e)),
             exp.CurrentUser: lambda *_: "CURRENT_USER",
             exp.AtTimeZone: lambda self, e: self.func(
@@ -373,6 +393,7 @@ def datatype_sql(self, expression: exp.DataType) -> str:
             exp.Date: rename_func("TO_DATE"),
             # https://docs.exasol.com/db/latest/sql_references/functions/alphabeticallistfunctions/to_timestamp.htm
             exp.Timestamp: rename_func("TO_TIMESTAMP"),
+            exp.Quarter: lambda self, e: f"CEIL(MONTH(TO_DATE({self.sql(e, 'this')}))/3)",
         }
 
         def converttimezone_sql(self, expression: exp.ConvertTimezone) -> str:

tests/dialects/test_exasol.py

@@ -407,26 +407,34 @@ def test_datetime_functions(self):
             "SELECT CAST(CAST(CURRENT_TIMESTAMP() AS TIMESTAMP) AT TIME ZONE 'CET' AS DATE) - 1",
             "SELECT CAST(CONVERT_TZ(CAST(CURRENT_TIMESTAMP() AS TIMESTAMP), 'UTC', 'CET') AS DATE) - 1",
         )
+        units = ["MM", "QUARTER", "WEEK", "MINUTE", "YEAR"]
+        for unit in units:
+            with self.subTest(f"Testing TO_CHAR with format '{unit}'"):
+                self.validate_all(
+                    f"SELECT TRUNC(CAST('2006-12-31' AS DATE), '{unit}') AS TRUNC",
+                    write={
+                        "exasol": f"SELECT DATE_TRUNC('{unit}', DATE '2006-12-31') AS TRUNC",
+                        "presto": f"SELECT DATE_TRUNC('{unit}', CAST('2006-12-31' AS DATE)) AS TRUNC",
+                        "databricks": f"SELECT TRUNC(CAST('2006-12-31' AS DATE), '{unit}') AS TRUNC",
+                    },
+                )
 
-        self.validate_all(
-            "SELECT TRUNC(CAST('2006-12-31' AS DATE), 'MM') AS TRUNC",
-            write={
-                "exasol": "SELECT TRUNC(CAST('2006-12-31' AS DATE), 'MM') AS TRUNC",
-                "presto": "SELECT DATE_TRUNC('MM', CAST('2006-12-31' AS DATE)) AS TRUNC",
-                "databricks": "SELECT TRUNC(CAST('2006-12-31' AS DATE), 'MM') AS TRUNC",
-            },
-        )
-        self.validate_all(
-            "SELECT DATE_TRUNC('minute', TIMESTAMP '2006-12-31 23:59:59') DATE_TRUNC",
-            write={
-                "exasol": "SELECT DATE_TRUNC('MINUTE', CAST('2006-12-31 23:59:59' AS TIMESTAMP)) AS DATE_TRUNC",
-                "presto": "SELECT DATE_TRUNC('MINUTE', CAST('2006-12-31 23:59:59' AS TIMESTAMP)) AS DATE_TRUNC",
-                "databricks": "SELECT DATE_TRUNC('MINUTE', CAST('2006-12-31 23:59:59' AS TIMESTAMP)) AS DATE_TRUNC",
-            },
-        )
-        self.validate_identity(
-            "SELECT DAY_OF_WEEK('2023-01-01')", "SELECT CAST(TO_CHAR('2023-01-01', 'D') AS INTEGER)"
-        )
+                self.validate_all(
+                    f"SELECT DATE_TRUNC('{unit}', TIMESTAMP '2006-12-31T23:59:59') DATE_TRUNC",
+                    write={
+                        "exasol": f"SELECT DATE_TRUNC('{unit}', TIMESTAMP '2006-12-31 23:59:59') AS DATE_TRUNC",
+                        "presto": f"SELECT DATE_TRUNC('{unit}', CAST('2006-12-31T23:59:59' AS TIMESTAMP)) AS DATE_TRUNC",
+                        "databricks": f"SELECT DATE_TRUNC('{unit}', CAST('2006-12-31T23:59:59' AS TIMESTAMP)) AS DATE_TRUNC",
+                    },
+                )
+                self.validate_all(
+                    f"SELECT DATE_TRUNC('{unit}', CURRENT_TIMESTAMP) DATE_TRUNC",
+                    write={
+                        "exasol": f"SELECT DATE_TRUNC('{unit}', CURRENT_TIMESTAMP()) AS DATE_TRUNC",
+                        "presto": f"SELECT DATE_TRUNC('{unit}', CURRENT_TIMESTAMP) AS DATE_TRUNC",
+                        "databricks": f"SELECT DATE_TRUNC('{unit}', CURRENT_TIMESTAMP()) AS DATE_TRUNC",
+                    },
+                )
 
         from sqlglot.dialects.exasol import DATE_UNITS