Merge pull request #25 from ChangxingJiang/24-dev

#24：新增 DELETE 语句解析逻辑

metasequoia_sql/core/node.py

@@ -178,6 +178,9 @@
     "ASTUpdateSetClause",  # UPDATE 语句中的 SET 子句
     "ASTUpdateStatement",  # UPDATE 语句
 
+    # ------------------------------ 抽象语法树（AST）节点的 DELETE 语句节点 ------------------------------
+    "ASTDeleteStatement",  # DELETE 语句
+
     # ------------------------------ 抽象语法树（AST）节点的 SHOW 语句节点 ------------------------------
     "ASTShowDatabasesStatement",  # SHOW DATABASES 语句
     "ASTShowTablesStatement",  # SHOW TABLES 语句
@@ -1865,6 +1868,27 @@ def source(self, sql_type: SQLType = SQLType.DEFAULT) -> str:
         return result
 
 
+@dataclasses.dataclass(slots=True, frozen=True, eq=True)
+class ASTDeleteStatement(ASTStatementBase):
+    """DELETE 语句"""
+
+    table_name: ASTTableNameExpression = dataclasses.field(kw_only=True)
+    where_clause: Optional[ASTWhereClause] = dataclasses.field(kw_only=True)
+    order_by_clause: Optional[ASTOrderByClause] = dataclasses.field(kw_only=True)
+    limit_clause: Optional[ASTLimitClause] = dataclasses.field(kw_only=True)
+
+    def source(self, sql_type: SQLType = SQLType.DEFAULT) -> str:
+        """返回语法节点的 SQL 源码"""
+        result = f"DELETE FROM {self.table_name.source(sql_type)} "
+        if self.where_clause is not None:
+            result += f" {self.where_clause.source(sql_type)}"
+        if self.order_by_clause is not None:
+            result += f" {self.order_by_clause.source(sql_type)}"
+        if self.limit_clause is not None:
+            result += f" {self.limit_clause.source(sql_type)}"
+        return result
+
+
 @dataclasses.dataclass(slots=True, frozen=True, eq=True)
 class ASTShowDatabasesStatement(ASTStatementBase):
     """SHOW DATABASES 语句"""

metasequoia_sql/core/parser.py

@@ -2240,6 +2240,27 @@ def _parse_update_statement(cls, scanner: TokenScanner,
             limit_clause=limit_clause
         )
 
+    @classmethod
+    def parse_delete_statement(cls, scanner_or_string: ScannerOrString,
+                               sql_type: SQLType = SQLType.DEFAULT) -> node.ASTDeleteStatement:
+        """解析 UPDATE 语句"""
+        scanner = cls._unify_input_scanner(scanner_or_string, sql_type=sql_type)
+        return cls._parse_delete_statement(scanner, sql_type)
+
+    @classmethod
+    def _parse_delete_statement(cls, scanner: TokenScanner, sql_type: SQLType) -> node.ASTDeleteStatement:
+        scanner.match("DELETE", "FROM")
+        table_name = cls._parse_table_name_expression(scanner)
+        where_clause = cls._parse_where_clause(scanner, sql_type)
+        order_by_clause = cls._parse_order_by_clause(scanner, sql_type)
+        limit_clause = cls._parse_limit_clause(scanner)
+        return node.ASTDeleteStatement(
+            table_name=table_name,
+            where_clause=where_clause,
+            order_by_clause=order_by_clause,
+            limit_clause=limit_clause
+        )
+
     @classmethod
     def parse_show_columns_statement(cls, scanner_or_string: ScannerOrString,
                                      sql_type: SQLType = SQLType.DEFAULT) -> node.ASTShowColumnsStatement:
@@ -2269,6 +2290,10 @@ def parse_statements(cls, scanner_or_string: ScannerOrString,
             if scanner.search_one_type_str_use_upper("SET"):
                 statement_list.append(cls._parse_set_statement(scanner))
 
+            # 解析 DELETE 语句
+            elif scanner.search_two_type_str_use_upper("DELETE", "FROM"):
+                statement_list.append(cls._parse_delete_statement(scanner, sql_type))
+
             # 解析 DROP TABLE 语句
             elif scanner.search_two_type_str_use_upper("DROP", "TABLE"):
                 statement_list.append(cls._parse_drop_table_statement(scanner))

scripts/tests/test_parse_statement.py

@@ -0,0 +1,15 @@
+"""
+语句级解析样例
+"""
+
+import unittest
+
+from metasequoia_sql import SQLParser
+
+
+class TestDolphinSchedulerMysql(unittest.TestCase):
+    """使用海豚调度元数据的测试用例"""
+
+    def test_delete_statement(self):
+        """测试 DELETE 语句解析"""
+        SQLParser.parse_statements("DELETE FROM table_1 WHERE column1 = '3'")