Question

我们正在运行的网络应用使用的其中一个查询如下：

SELECT
       p.id, r.id AS report_id, tr.result_id,
       r.report_date, r.department, r.reportStatus, rs.specimen,
       tr.name, tr.value, tr.flag, tr.unit, tr.reference_range
FROM patients AS p
INNER JOIN
    patients_reports AS pr ON pr.patient_id = p.id
INNER JOIN
    reports AS r ON pr.report_id = r.id
INNER JOIN
    results AS rs ON r.id = rs.report_id
INNER JOIN
    test_results AS tr ON rs.id = tr.result_id
WHERE pr.patient_id = 17548
ORDER BY rs.specimen, tr.name, r.report_date;

解释计划如下：

+----+-------------+-------+--------+---------------+-----------+---------+-------------------+--------+----------------------------------------------+
| id | select_type | table | type   | possible_keys | key       | key_len | ref               | rows   | Extra                                        |
+----+-------------+-------+--------+---------------+-----------+---------+-------------------+--------+----------------------------------------------+
|  1 | SIMPLE      | p     | const  | PRIMARY       | PRIMARY   | 4       | const             |      1 | Using index; Using temporary; Using filesort |
|  1 | SIMPLE      | rs    | ALL    | PRIMARY       | NULL      | NULL    | NULL              | 152817 |                                              |
|  1 | SIMPLE      | r     | eq_ref | PRIMARY       | PRIMARY   | 4       | demo.rs.report_id |      1 |                                              |
|  1 | SIMPLE      | pr    | eq_ref | PRIMARY       | PRIMARY   | 8       | const,demo.r.id   |      1 | Using where; Using index                     |
|  1 | SIMPLE      | tr    | ref    | result_id     | result_id | 5       | demo.rs.id        |      1 | Using where                                  |
+----+-------------+-------+--------+---------------+-----------+---------+-------------------+--------+----------------------------------------------+

查询返回27371行。目前test_results中有152730行。这只是少量的演示数据。

我试图让查询更有效率，但我无法让它更快地执行。我已经看过关于stackoverflow的文档和问题的各种文章，但是无法解决这个问题。

我尝试删除其中一个连接，如下所示：

SELECT
       pr.patient_id, r.id AS report_id, tr.result_id,
       r.report_date, r.department, r.reportStatus, rs.specimen,
       tr.name, tr.value, tr.flag, tr.unit, tr.reference_range
FROM patients_reports AS pr
INNER JOIN
    reports AS r ON pr.report_id = r.id
INNER JOIN
    results AS rs ON r.id = rs.report_id
INNER JOIN
    test_results AS tr ON rs.id = tr.result_id
WHERE pr.patient_id = 17548
ORDER BY rs.specimen, tr.name, r.report_date;

查询计划如下：

+----+-------------+-------+--------+---------------+-----------+---------+-------------------+--------+---------------------------------+
| id | select_type | table | type   | possible_keys | key       | key_len | ref               | rows   | Extra                           |
+----+-------------+-------+--------+---------------+-----------+---------+-------------------+--------+---------------------------------+
|  1 | SIMPLE      | rs    | ALL    | PRIMARY       | NULL      | NULL    | NULL              | 152817 | Using temporary; Using filesort |
|  1 | SIMPLE      | r     | eq_ref | PRIMARY       | PRIMARY   | 4       | demo.rs.report_id |      1 |                                 |
|  1 | SIMPLE      | pr    | eq_ref | PRIMARY       | PRIMARY   | 8       | const,demo.r.id   |      1 | Using where; Using index        |
|  1 | SIMPLE      | tr    | ref    | result_id     | result_id | 5       | demo.rs.id        |      1 | Using where                     |
+----+-------------+-------+--------+---------------+-----------+---------+-------------------+--------+---------------------------------+

所以差别不大。

我已经尝试重新排列查询并使用STRAIGHT_JOIN等等，但我没有到达任何地方。

我很欣赏有关如何优化查询的一些建议。感谢。

编辑：唉！我没有关于results.report_id的索引，但它似乎没有帮助：

+----+-------------+-------+--------+-------------------+-----------+---------+-------------------+--------+---------------------------------+
| id | select_type | table | type   | possible_keys     | key       | key_len | ref               | rows   | Extra                           |
+----+-------------+-------+--------+-------------------+-----------+---------+-------------------+--------+---------------------------------+
|  1 | SIMPLE      | rs    | ALL    | PRIMARY,report_id | NULL      | NULL    | NULL              | 152817 | Using temporary; Using filesort |
|  1 | SIMPLE      | r     | eq_ref | PRIMARY           | PRIMARY   | 4       | demo.rs.report_id |      1 |                                 |
|  1 | SIMPLE      | pr    | eq_ref | PRIMARY           | PRIMARY   | 8       | const,demo.r.id   |      1 | Using where; Using index        |
|  1 | SIMPLE      | tr    | ref    | result_id         | result_id | 5       | demo.rs.id        |      1 | Using where                     |
+----+-------------+-------+--------+-------------------+-----------+---------+-------------------+--------+---------------------------------+

EDIT2：

patients_reports看起来像这样：

+------------+---------+------+-----+---------+-------+
| Field      | Type    | Null | Key | Default | Extra |
+------------+---------+------+-----+---------+-------+
| patient_id | int(11) | NO   | PRI | 0       |       |
| report_id  | int(11) | NO   | PRI | 0       |       |
+------------+---------+------+-----+---------+-------+

EDIT3：

添加results.report_id索引并按@DRapp的建议再次尝试STRAIGHT_JOIN：

SELECT STRAIGHT_JOIN
       r.id AS report_id, tr.result_id,
       r.report_date, r.department, r.reportStatus, rs.specimen,
       tr.name, tr.value, tr.flag, tr.unit, tr.reference_range
FROM patients_reports AS pr
INNER JOIN
    reports AS r ON pr.report_id = r.id
INNER JOIN
    results AS rs ON r.id = rs.report_id
INNER JOIN
    test_results AS tr ON rs.id = tr.result_id
WHERE pr.patient_id = 17548
ORDER BY rs.specimen, tr.name, r.report_date;

计划如下：

+----+-------------+-------+--------+-------------------+-----------+---------+-------------------+------+----------------------------------------------+
| id | select_type | table | type   | possible_keys     | key       | key_len | ref               | rows | Extra                                        |
+----+-------------+-------+--------+-------------------+-----------+---------+-------------------+------+----------------------------------------------+
|  1 | SIMPLE      | pr    | ref    | PRIMARY           | PRIMARY   | 4       | const             | 3646 | Using index; Using temporary; Using filesort |
|  1 | SIMPLE      | r     | eq_ref | PRIMARY           | PRIMARY   | 4       | demo.pr.report_id |    1 |                                              |
|  1 | SIMPLE      | rs    | ref    | PRIMARY,report_id | report_id | 5       | demo.r.id         |  764 | Using where                                  |
|  1 | SIMPLE      | tr    | ref    | result_id         | result_id | 5       | demo.rs.id        |    1 | Using where                                  |
+----+-------------+-------+--------+-------------------+-----------+---------+-------------------+------+----------------------------------------------+

所以我认为看起来好多了，但我不确定该怎么说。此外，查询似乎仍然需要与以前相同的时间。

Answer 1

我会使用STRAIGHT_JOIN并使用第一个包含patients_reports表的查询，然后继续加入患者表中以获取其姓名信息。另外，如果我没有看到它，那么PATIENT_ID列中的patients_reports表是否有一个索引，或者作为复合索引键的第一个元素？

此外，确保RESULTS在Report_ID上有索引，与TEST_RESULTS（Result_ID索引）相同

Answer 2

results.report_id索引了吗？它没有找到一个键并且正在进行表扫描。我假设results.id实际上是主键。

另外，如果它的report_id是主键，而且它是INNODB，它应该聚集在该索引上，所以绝对不知道为什么如果以这种方式配置的话，它不会快速尖叫。

使用多个连接优化MySQL查询

2 个答案: