小编M.A*_*lay的帖子

CREATE TABLE test (
id INT NOT NULL,
last_name CHAR(30) NOT NULL,
first_name CHAR(30) NOT NULL,
PRIMARY KEY (id),
KEY `first_name` (first_name),
KEY `last_name` (last_name),
KEY `last_first` (last_name,first_name)
);

如果一个表在同一字段上有单个索引和复合索引，如果我有如下查询，这很好吗：

SELECT * FROM test WHERE first_name = 'A';
SELECT * FROM test WHERE last_name= 'A';
SELECT * FROM test WHERE last_name= 'A' AND first_name = 'A';