语句如下：

    1. select_stmt:
    2.       SELECT [ALL | DISTINCT] select_expression_list
    3.        [FROM table_reference_list]
    4.       [WHERE condition]
    5.       [GROUP BY group_expression_list [WITH ROLLUP] [HAVING condition]]
    6.       [ORDER BY order_expression_list]
    7.       [LIMIT limit_offset]
    8.         [FOR UPDATE];
    9.     | select_stmt set_operation select_stmt;
    11. select_expression_list:
    12.     select_expression [, select_expression ...]
    14. select_expression:
    15.       table_name.*
    16.     | table_alias_name.*
    17.     | expression [[AS] column_alias_name]
    19. table_reference_list:
    20.     table_reference [, table_reference ...]
    22. table_reference:
    23.       simple_table
    24.     | joined_table
    26. simple_table:
    27.       DUAL
    28.     | table_factor [partition_option] [[AS] table_alias_name]
    29.     | (select_stmt) [AS] table_alias_name
    30.     | (table_reference_list)
    32. joined_table:
    33.       table_reference [INNER] JOIN simple_table [join_condition]
    34.     | table_reference outer_join_type JOIN simple_table join_condition
    36. partition_option:
    37.     PARTITION (partition_name_list)
    39. partition_name_list:
    40.     partition_name [, partition_name ...]
    42. outer_join_type:
    43.     {LEFT | RIGHT | FULL} [OUTER]
    45. join_condition:
    46.     ON expression
    48. condition:
    49.     expression
    51. group_expression_list:
    52.     group_expression [, group_expression ...]
    54. group_expression:
    55.     expression [ASC | DESC]
    57. order_expression_list:
    58.     order_expression [, order_expression ...]
    60. order_expression:
    61.     expression [ASC | DESC]
    63. limit_offset:
    64.       offset_row_count, limit_row_count
    65.     | limit_row_count [OFFSET offset_row_count]
    67. limit_row_count | offset_row_count:
    68.     INT_VALUE
    70. set_operation:
    71.       UNION
    72.     | EXCEPT
    73.     | INTERSECT