这个问题是关于查询优化,以避免通过 PHP 多次调用数据库。
所以这是场景,我有两个表,一个包含您可以称之为引用表的信息,另一个是数据表,字段 key1 和 key2 在两个表,基于这些字段,我们可以加入它们。
我不知道查询是否可以比我现在做的更简单,我想实现的是:
I would like to find distinct
key1,key2,info1,info2frommain_infotable, whenever serial value is less than 10 andkey1,key2of both table matches, and then group them byinfo1,info2, while grouping count the repeatedkey1,key2for duplicates ofinfo1,info2fields andgroup_concatthose keys
表main_info的内容
MariaDB [demos]> select * from main_info;
+------+------+-------+-------+----------+
| key1 | key2 | info1 | info2 | date |
+------+------+-------+-------+----------+
| 1 | 1 | 15 | 90 | 20120501 |
| 1 | 2 | 14 | 92 | 20120601 |
| 1 | 3 | 15 | 82 | 20120801 |
| 1 | 4 | 15 | 82 | 20120801 |
| 1 | 5 | 15 | 82 | 20120802 |
| 2 | 1 | 17 | 90 | 20130302 |
| 2 | 2 | 17 | 90 | 20130302 |
| 2 | 3 | 17 | 90 | 20130302 |
| 2 | 4 | 16 | 88 | 20130601 |
+------+------+-------+-------+----------+
9 rows in set (0.00 sec)
表 product1 的内容
MariaDB [demos]> select * from product1;
+------+------+--------+--------------+
| key1 | key2 | serial | product_data |
+------+------+--------+--------------+
| 1 | 1 | 0 | NaN |
| 1 | 1 | 1 | NaN |
| 1 | 1 | 2 | NaN |
| 1 | 1 | 3 | NaN |
| 1 | 2 | 0 | 12.556 |
| 1 | 2 | 1 | 13.335 |
| 1 | 3 | 1 | NaN |
| 1 | 3 | 2 | 13.556 |
| 1 | 3 | 3 | 14.556 |
| 1 | 4 | 3 | NaN |
| 1 | 5 | 3 | NaN |
| 2 | 1 | 0 | 12.556 |
| 2 | 1 | 1 | 13.553 |
| 2 | 1 | 2 | NaN |
| 2 | 2 | 12 | 129 |
| 2 | 3 | 22 | NaN |
+------+------+--------+--------------+
16 rows in set (0.00 sec)
通过 PHP,我在当前上下文 serial 中对表 main_info 的字段 info1 和 info2 进行分组,表product1的product_data,一个接一个多次(如你所见,这里我运行了两次查询)
对于字段serial - 第一个查询
MariaDB [demos]> select * , count(*) as serial_count,GROUP_CONCAT(key1,' ',key2) as serial_ids from
-> (
-> SELECT distinct
-> if(b.serial < 10,a.key1,null) AS `key1`,
-> if(b.serial < 10,a.key2,null) AS `key2`,
-> if(b.serial < 10,a.info1,null) AS `info1`,
-> if(b.serial < 10,a.info2,null) AS `info2`
-> FROM main_info a inner join product1 b on a.key1 = b.key1 AND a.key2= b.key2
-> ) as sub group by info1,info2
-> ;
+------+------+-------+-------+--------------+-------------+
| key1 | key2 | info1 | info2 | serial_count | serial_ids |
+------+------+-------+-------+--------------+-------------+
| NULL | NULL | NULL | NULL | 1 | NULL |
| 1 | 2 | 14 | 92 | 1 | 1 2 |
| 1 | 3 | 15 | 82 | 3 | 1 3,1 4,1 5 |
| 1 | 1 | 15 | 90 | 1 | 1 1 |
| 2 | 1 | 17 | 90 | 1 | 2 1 |
+------+------+-------+-------+--------------+-------------+
5 rows in set (0.00 sec)
对于字段 product_data - 第二个查询
MariaDB [demos]> select * , count(*) as product_data_count,GROUP_CONCAT(key1,' ',key2) as product_data_ids from
-> (
-> SELECT distinct
-> if(b.product_data IS NOT NULL,a.key1,null) AS `key1`,
-> if(b.product_data IS NOT NULL,a.key2,null) AS `key2`,
-> if(b.product_data IS NOT NULL,a.info1,null) AS `info1`,
-> if(b.product_data IS NOT NULL,a.info2,null) AS `info2`
-> FROM main_info a inner join product1 b on a.key1 = b.key1 AND a.key2= b.key2
-> ) as sub group by info1,info2
-> ;
+------+------+-------+-------+--------------------+------------------+
| key1 | key2 | info1 | info2 | product_data_count | product_data_ids |
+------+------+-------+-------+--------------------+------------------+
| 1 | 2 | 14 | 92 | 1 | 1 2 |
| 1 | 3 | 15 | 82 | 3 | 1 3,1 4,1 5 |
| 1 | 1 | 15 | 90 | 1 | 1 1 |
| 2 | 2 | 17 | 90 | 3 | 2 2,2 3,2 1 |
+------+------+-------+-------+--------------------+------------------+
4 rows in set (0.01 sec)
我想使用一个查询获得这样的输出,Group by info1, info2
+------+------+-------+-------+--------------+-------------+--------------------+------------------+
| key1 | key2 | info1 | info2 | serial_count | serial_ids | product_data_count | product_data_ids |
+------+------+-------+-------+--------------+-------------+--------------------+------------------+
| NULL | NULL | NULL | NULL | 1 | NULL | NULL | NULL |
| 1 | 2 | 14 | 92 | 1 | 1 2 | 1 | 1 2 |
| 1 | 3 | 15 | 82 | 3 | 1 3,1 4,1 5 | 3 | 1 3,1 4,1 5 |
| 1 | 1 | 15 | 90 | 1 | 1 1 | 1 | 1 1 |
| 2 | 1 | 17 | 90 | 1 | 2 1 | 3 | 2 2,2 3,2 1 |
+------+------+-------+-------+--------------+-------------+--------------------+------------------+
表格结构如下
DROP TABLE IF EXISTS `main_info`;
CREATE TABLE `main_info` (
`key1` int(11) NOT NULL,
`key2` int(11) NOT NULL,
`info1` int(11) NOT NULL,
`info2` int(11) NOT NULL,
`date` int(11) NOT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
LOCK TABLES `main_info` WRITE;
INSERT INTO `main_info` VALUES (1,1,15,90,20120501),(1,2,14,92,20120601),(1,3,15,82,20120801),(1,4,15,82,20120801),(1,5,15,82,20120802),(2,1,17,90,20130302),(2,2,17,90,20130302),(2,3,17,90,20130302),(2,4,16,88,20130601);
UNLOCK TABLES;
DROP TABLE IF EXISTS `product1`;
CREATE TABLE `product1` (
`key1` int(11) NOT NULL,
`key2` int(11) NOT NULL,
`serial` int(11) NOT NULL,
`product_data` varchar(1000) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
LOCK TABLES `product1` WRITE;
INSERT INTO `product1` VALUES (1,1,0,'NaN'),(1,1,1,'NaN'),(1,1,2,'NaN'),(1,1,3,'NaN'),(1,2,0,'12.556'),(1,2,1,'13.335'),(1,3,1,'NaN'),(1,3,2,'13.556'),(1,3,3,'14.556'),(1,4,3,'NaN'),(1,5,3,'NaN'),(2,1,0,'12.556'),(2,1,1,'13.553'),(2,1,2,'NaN'),(2,2,12,'129'),(2,3,22,'NaN');
UNLOCK TABLES;
有人请帮助我在一次查询中获得结果。
最佳答案
如何将您的两个查询与 JOIN 结合起来?
SQL:
SELECT
tbl1.key1, tbl1.key2, tbl1.info1, tbl1.info2, tbl1.serial_count, tbl1.serial_ids,
tbl2.product_data_count, tbl2.product_data_ids
FROM
(
select * , count(*) as serial_count,GROUP_CONCAT(key1,' ',key2) as serial_ids from
(
SELECT distinct
if(b.serial < 10,a.key1,null) AS `key1`,
if(b.serial < 10,a.key2,null) AS `key2`,
if(b.serial < 10,a.info1,null) AS `info1`,
if(b.serial < 10,a.info2,null) AS `info2`
FROM main_info a inner join product1 b on a.key1 = b.key1 AND a.key2= b.key2
) as sub group by info1,info2
) tbl1
LEFT OUTER JOIN
(
select * , count(*) as product_data_count,GROUP_CONCAT(key1,' ',key2) as product_data_ids from
(
SELECT distinct
if(b.product_data IS NOT NULL,a.key1,null) AS `key1`,
if(b.product_data IS NOT NULL,a.key2,null) AS `key2`,
if(b.product_data IS NOT NULL,a.info1,null) AS `info1`,
if(b.product_data IS NOT NULL,a.info2,null) AS `info2`
FROM main_info a inner join product1 b on a.key1 = b.key1 AND a.key2= b.key2
) as sub group by info1,info2
) tbl2
ON tbl1.info1 = tbl2.info1 AND tbl1.info2 = tbl2.info2
ORDER BY 3,4
;
输出:
mysql> SELECT
-> tbl1.key1, tbl1.key2, tbl1.info1, tbl1.info2, tbl1.serial_count, tbl1.serial_ids,
-> tbl2.product_data_count, tbl2.product_data_ids
-> FROM
-> (
-> select * , count(*) as serial_count,GROUP_CONCAT(key1,' ',key2) as serial_ids from
-> (
-> SELECT distinct
-> if(b.serial < 10,a.key1,null) AS `key1`,
-> if(b.serial < 10,a.key2,null) AS `key2`,
-> if(b.serial < 10,a.info1,null) AS `info1`,
-> if(b.serial < 10,a.info2,null) AS `info2`
-> FROM main_info a inner join product1 b on a.key1 = b.key1 AND a.key2= b.key2
-> ) as sub group by info1,info2
-> ) tbl1
-> LEFT OUTER JOIN
-> (
-> select * , count(*) as product_data_count,GROUP_CONCAT(key1,' ',key2) as product_data_ids from
-> (
-> SELECT distinct
-> if(b.product_data IS NOT NULL,a.key1,null) AS `key1`,
-> if(b.product_data IS NOT NULL,a.key2,null) AS `key2`,
-> if(b.product_data IS NOT NULL,a.info1,null) AS `info1`,
-> if(b.product_data IS NOT NULL,a.info2,null) AS `info2`
-> FROM main_info a inner join product1 b on a.key1 = b.key1 AND a.key2= b.key2
-> ) as sub group by info1,info2
-> ) tbl2
-> ON tbl1.info1 = tbl2.info1 AND tbl1.info2 = tbl2.info2
-> ORDER BY 3,4
-> ;
+------+------+-------+-------+--------------+-------------+--------------------+------------------+
| key1 | key2 | info1 | info2 | serial_count | serial_ids | product_data_count | product_data_ids |
+------+------+-------+-------+--------------+-------------+--------------------+------------------+
| NULL | NULL | NULL | NULL | 1 | NULL | NULL | NULL |
| 1 | 2 | 14 | 92 | 1 | 1 2 | 1 | 1 2 |
| 1 | 3 | 15 | 82 | 3 | 1 3,1 4,1 5 | 3 | 1 3,1 4,1 5 |
| 1 | 1 | 15 | 90 | 1 | 1 1 | 1 | 1 1 |
| 2 | 1 | 17 | 90 | 1 | 2 1 | 3 | 2 2,2 3,2 1 |
+------+------+-------+-------+--------------+-------------+--------------------+------------------+
5 rows in set (0.01 sec)
mysql> select version();
+-----------------+
| version() |
+-----------------+
| 10.1.10-MariaDB |
+-----------------+
1 row in set (0.00 sec)
关于重复键的Mysql group_concat和1个查询中多列的重复计数(查询优化),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/35538092/
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