Postgres & T-SQL: Drop Function

src/sqlfluff/dialects/dialect_postgres.py

@@ -474,6 +474,29 @@ class CreateFunctionStatementSegment(BaseSegment):
     )
 
 
+@postgres_dialect.segment()
+class DropFunctionStatementSegment(BaseSegment):
+    """A `DROP FUNCTION` statement.
+
+    As per the specification: https://www.postgresql.org/docs/14/sql-dropfunction.html
+    """
+
+    type = "drop_function_statement"
+
+    match_grammar = Sequence(
+        "DROP",
+        "FUNCTION",
+        Ref("IfExistsGrammar", optional=True),
+        Delimited(
+            Sequence(
+                Ref("FunctionNameSegment"),
+                Ref("FunctionParameterListGrammar", optional=True),
+            )
+        ),
+        OneOf("CASCADE", "RESTRICT", optional=True),
+    )
+
+
 @postgres_dialect.segment()
 class WellKnownTextGeometrySegment(BaseSegment):
     """A Data Type Segment to identify Well Known Text Geometric Data Types.
@@ -2141,6 +2164,7 @@ class StatementSegment(BaseSegment):
             Ref("CreateTableAsStatementSegment"),
             Ref("AlterTriggerStatementSegment"),
             Ref("SetStatementSegment"),
+            Ref("DropFunctionStatementSegment"),
         ],
     )
 

src/sqlfluff/dialects/dialect_tsql.py

@@ -248,6 +248,7 @@ class StatementSegment(ansi_dialect.get_segment("StatementSegment")):  # type: i
             Ref("DropStatisticsStatementSegment"),
             Ref("DropProcedureStatementSegment"),
             Ref("UpdateStatisticsStatementSegment"),
+            Ref("DropFunctionStatementSegment"),
         ],
     )
 
@@ -875,6 +876,24 @@ class CreateFunctionStatementSegment(BaseSegment):
     )
 
 
+@tsql_dialect.segment()
+class DropFunctionStatementSegment(BaseSegment):
+    """A `DROP FUNCTION` statement.
+
+    As per specification https://docs.microsoft.com/en-us/sql/t-sql/statements/drop-function-transact-sql?view=sql-server-ver15
+    """
+
+    type = "drop_function_statement"
+
+    match_grammar = Sequence(
+        "DROP",
+        "FUNCTION",
+        Ref("IfExistsGrammar", optional=True),
+        Delimited(Ref("FunctionNameSegment")),
+        Ref("DelimiterSegment", optional=True),
+    )
+
+
 @tsql_dialect.segment()
 class SetStatementSegment(BaseSegment):
     """A Set statement.

test/fixtures/dialects/postgres/postgres_drop_function.sql

@@ -0,0 +1,5 @@
+DROP FUNCTION sqrt(integer);
+DROP FUNCTION sqrt(integer), sqrt(bigint);
+DROP FUNCTION update_employee_salaries;
+DROP FUNCTION update_employee_salaries();
+DROP FUNCTION IF EXISTS foo (IN my_var integer, VARIADIC my_var_2 text);

test/fixtures/dialects/postgres/postgres_drop_function.yml

@@ -0,0 +1,82 @@
+# YML test files are auto-generated from SQL files and should not be edited by
+# hand. To help enforce this, the "hash" field in the file must match a hash
+# computed by SQLFluff when running the tests. Please run
+# `python test/generate_parse_fixture_yml.py`  to generate them after adding or
+# altering SQL files.
+_hash: c03cd688fad76ef981e529184fbc95c3da919d6e393d39d53e1c9a8ba6b8bb23
+file:
+- statement:
+    drop_function_statement:
+    - keyword: DROP
+    - keyword: FUNCTION
+    - function_name:
+        function_name_identifier: sqrt
+    - base:
+        bracketed:
+          start_bracket: (
+          data_type:
+            data_type_identifier: integer
+          end_bracket: )
+- statement_terminator: ;
+- statement:
+    drop_function_statement:
+    - keyword: DROP
+    - keyword: FUNCTION
+    - function_name:
+        function_name_identifier: sqrt
+    - base:
+        bracketed:
+          start_bracket: (
+          data_type:
+            data_type_identifier: integer
+          end_bracket: )
+    - comma: ','
+    - function_name:
+        function_name_identifier: sqrt
+    - base:
+        bracketed:
+          start_bracket: (
+          data_type:
+            data_type_identifier: bigint
+          end_bracket: )
+- statement_terminator: ;
+- statement:
+    drop_function_statement:
+    - keyword: DROP
+    - keyword: FUNCTION
+    - function_name:
+        function_name_identifier: update_employee_salaries
+- statement_terminator: ;
+- statement:
+    drop_function_statement:
+    - keyword: DROP
+    - keyword: FUNCTION
+    - function_name:
+        function_name_identifier: update_employee_salaries
+    - base:
+        bracketed:
+          start_bracket: (
+          end_bracket: )
+- statement_terminator: ;
+- statement:
+    drop_function_statement:
+    - keyword: DROP
+    - keyword: FUNCTION
+    - keyword: IF
+    - keyword: EXISTS
+    - function_name:
+        function_name_identifier: foo
+    - base:
+        bracketed:
+        - start_bracket: (
+        - keyword: IN
+        - parameter: my_var
+        - data_type:
+            data_type_identifier: integer
+        - comma: ','
+        - keyword: VARIADIC
+        - parameter: my_var_2
+        - data_type:
+            data_type_identifier: text
+        - end_bracket: )
+- statement_terminator: ;

test/fixtures/dialects/tsql/drop_function.sql

@@ -0,0 +1,2 @@
+DROP FUNCTION Sales.fn_SalesByStore;
+DROP FUNCTION IF EXISTS sales, sales2;

test/fixtures/dialects/tsql/drop_function.yml

@@ -0,0 +1,29 @@
+# YML test files are auto-generated from SQL files and should not be edited by
+# hand. To help enforce this, the "hash" field in the file must match a hash
+# computed by SQLFluff when running the tests. Please run
+# `python test/generate_parse_fixture_yml.py`  to generate them after adding or
+# altering SQL files.
+_hash: d14f2b6b16bb2743a5c4f8439be4a40e30bf5a63afca8622686674ef4445013c
+file:
+  batch:
+  - statement:
+      drop_function_statement:
+      - keyword: DROP
+      - keyword: FUNCTION
+      - function_name:
+          identifier: Sales
+          dot: .
+          function_name_identifier: fn_SalesByStore
+      - statement_terminator: ;
+  - statement:
+      drop_function_statement:
+      - keyword: DROP
+      - keyword: FUNCTION
+      - keyword: IF
+      - keyword: EXISTS
+      - function_name:
+          function_name_identifier: sales
+      - comma: ','
+      - function_name:
+          function_name_identifier: sales2
+      - statement_terminator: ;