Table of Contents
原理分析:
总结:
Home Database Mysql Tutorial MySQL逗号分割字段的行列转换测试改进

MySQL逗号分割字段的行列转换测试改进

Jun 07, 2016 pm 02:51 PM
mysql Split Field Improve test Convert comma

p由于很多业务表因为历史原因或者性能原因,都使用了违反第一范式的设计模式。即同一个列中存储了多个属性值(具体结构见下表)。/pp这种模式下,应用常常需要将这个列依据分隔符进行分割,并得到列转行的结果。/p span class=cnblogs_code_copy/spanp style


<p>由于很多业务表因为历史原因或者性能原因,都使用了违反第一范式的设计模式。即同一个列中存储了多个属性值(具体结构见下表)。</p><p>这种模式下,应用常常需要将这个列依据分隔符进行分割,并得到列转行的结果。</p>
Copy after login
<span class="cnblogs_code_copy"></span><p style="margin: 10px auto; line-height: 19px; font-family: verdana, sans-serif; font-size: 13px;">表数据:</p>
Copy after login
ID Value
1 tiny,small,big
2 small,medium
3 tiny,big

 

期望得到结果:

ID Value
1 tiny
1 small
1 big
2 small
2 medium
3 tiny
3 big

 

<span style="line-height: 1.5;">#需要处理的表
</span><span style="color: rgb(0, 0, 255); line-height: 1.5;">create</span> <span style="color: rgb(0, 0, 255); line-height: 1.5;">table</span> tbl_name (ID <span style="color: rgb(0, 0, 255); line-height: 1.5;">int</span> ,mSize <span style="color: rgb(0, 0, 255); line-height: 1.5;">varchar</span>(<span style="color: rgb(128, 0, 0); line-height: 1.5; font-weight: bold;">100</span><span style="line-height: 1.5;">));
</span><span style="color: rgb(0, 0, 255); line-height: 1.5;">insert</span> <span style="color: rgb(0, 0, 255); line-height: 1.5;">into</span> tbl_name <span style="color: rgb(0, 0, 255); line-height: 1.5;">values</span> (<span style="color: rgb(128, 0, 0); line-height: 1.5; font-weight: bold;">1</span>,<span style="color: rgb(255, 0, 0); line-height: 1.5;">'</span><span style="color: rgb(255, 0, 0); line-height: 1.5;">tiny,small,big</span><span style="color: rgb(255, 0, 0); line-height: 1.5;">'</span><span style="line-height: 1.5;">);
</span><span style="color: rgb(0, 0, 255); line-height: 1.5;">insert</span> <span style="color: rgb(0, 0, 255); line-height: 1.5;">into</span> tbl_name <span style="color: rgb(0, 0, 255); line-height: 1.5;">values</span> (<span style="color: rgb(128, 0, 0); line-height: 1.5; font-weight: bold;">2</span>,<span style="color: rgb(255, 0, 0); line-height: 1.5;">'</span><span style="color: rgb(255, 0, 0); line-height: 1.5;">small,medium</span><span style="color: rgb(255, 0, 0); line-height: 1.5;">'</span><span style="line-height: 1.5;">);
</span><span style="color: rgb(0, 0, 255); line-height: 1.5;">insert</span> <span style="color: rgb(0, 0, 255); line-height: 1.5;">into</span> tbl_name <span style="color: rgb(0, 0, 255); line-height: 1.5;">values</span> (<span style="color: rgb(128, 0, 0); line-height: 1.5; font-weight: bold;">3</span>,<span style="color: rgb(255, 0, 0); line-height: 1.5;">'</span><span style="color: rgb(255, 0, 0); line-height: 1.5;">tiny,big</span><span style="color: rgb(255, 0, 0); line-height: 1.5;">'</span><span style="line-height: 1.5;">);

#用于循环的自增表
</span><span style="color: rgb(0, 0, 255); line-height: 1.5;">create</span> <span style="color: rgb(0, 0, 255); line-height: 1.5;">table</span> incre_table (AutoIncreID <span style="color: rgb(0, 0, 255); line-height: 1.5;">int</span><span style="line-height: 1.5;">);
</span><span style="color: rgb(0, 0, 255); line-height: 1.5;">insert</span> <span style="color: rgb(0, 0, 255); line-height: 1.5;">into</span> incre_table <span style="color: rgb(0, 0, 255); line-height: 1.5;">values</span> (<span style="color: rgb(128, 0, 0); line-height: 1.5; font-weight: bold;">1</span><span style="line-height: 1.5;">);
</span><span style="color: rgb(0, 0, 255); line-height: 1.5;">insert</span> <span style="color: rgb(0, 0, 255); line-height: 1.5;">into</span> incre_table <span style="color: rgb(0, 0, 255); line-height: 1.5;">values</span> (<span style="color: rgb(128, 0, 0); line-height: 1.5; font-weight: bold;">2</span><span style="line-height: 1.5;">);
</span><span style="color: rgb(0, 0, 255); line-height: 1.5;">insert</span> <span style="color: rgb(0, 0, 255); line-height: 1.5;">into</span> incre_table <span style="color: rgb(0, 0, 255); line-height: 1.5;">values</span> (<span style="color: rgb(128, 0, 0); line-height: 1.5; font-weight: bold;">3</span>);
Copy after login
复制代码

 

复制代码
<span style="color:rgb(0,0,255); line-height:1.5">select</span> a.ID,substring_index(substring_index(a.mSize,<span style="color:rgb(255,0,0); line-height:1.5">'</span><span style="color:rgb(255,0,0); line-height:1.5">,</span><span style="color:rgb(255,0,0); line-height:1.5">'</span>,b.AutoIncreID),<span style="color:rgb(255,0,0); line-height:1.5">'</span><span style="color:rgb(255,0,0); line-height:1.5">,</span><span style="color:rgb(255,0,0); line-height:1.5">'</span>,<span style="color:rgb(128,128,128); line-height:1.5">-</span><span style="color:rgb(128,0,0); line-height:1.5; font-weight:bold">1</span><span style="line-height:1.5">) 
</span><span style="color:rgb(0,0,255); line-height:1.5">from</span><span style="line-height:1.5"> 
tbl_name a
</span><span style="color:rgb(128,128,128); line-height:1.5">join</span><span style="line-height:1.5">
incre_table b
</span><span style="color:rgb(0,0,255); line-height:1.5">on</span> b.AutoIncreID <span style="color:rgb(128,128,128); line-height:1.5"> (length(a.mSize) <span style="color:rgb(128,128,128); line-height:1.5">-</span> length(<span style="color:rgb(255,0,255); line-height:1.5">replace</span>(a.mSize,<span style="color:rgb(255,0,0); line-height:1.5">'</span><span style="color:rgb(255,0,0); line-height:1.5">,</span><span style="color:rgb(255,0,0); line-height:1.5">'</span>,<span style="color:rgb(255,0,0); line-height:1.5">''</span>))<span style="color:rgb(128,128,128); line-height:1.5">+</span><span style="color:rgb(128,0,0); line-height:1.5; font-weight:bold">1</span><span style="line-height:1.5">)
</span><span style="color:rgb(0,0,255); line-height:1.5">order</span> <span style="color:rgb(0,0,255); line-height:1.5">by</span> a.ID;</span>
Copy after login
Copy after login
Copy after login

原理分析:

这个join最基本原理是笛卡尔积。通过这个方式来实现循环。

以下是具体问题分析:

length(a.Size) - length(replace(a.mSize,',',''))+1  表示了,按照逗号分割后,改列拥有的数值数量,下面简称n

复制代码
<span style="color:#00ff">select</span> a.ID,substring_index(substring_index(a.mSize,<span style="color:#ff00">'</span><span style="color:#ff00">,</span><span style="color:#ff00">'</span>,b.AutoIncreID),<span style="color:#ff00">'</span><span style="color:#ff00">,</span><span style="color:#ff00">'</span>,<span style="color:#808080">-</span><span style="color:#8000; font-weight:bold">1</span><span style="color:#000000">) 
</span><span style="color:#00ff">from</span><span style="color:#000000"> 
tbl_name a
</span><span style="color:#808080">join</span><span style="color:#000000">
incre_table b
</span><span style="color:#00ff">on</span> b.AutoIncreID <span style="color:#808080"> (length(a.mSize) <span style="color:#808080">-</span> length(<span style="color:#ff0ff">replace</span>(a.mSize,<span style="color:#ff00">'</span><span style="color:#ff00">,</span><span style="color:#ff00">'</span>,<span style="color:#ff00">''</span>))<span style="color:#808080">+</span><span style="color:#8000; font-weight:bold">1</span><span style="color:#000000">)
</span><span style="color:#00ff">order</span> <span style="color:#00ff">by</span> a.ID;</span>
Copy after login
复制代码

原理分析:

这个join最基本原理是笛卡尔积。通过这个方式来实现循环。

以下是具体问题分析:

length(a.Size) - length(replace(a.mSize,',',''))+1  表示了,按照逗号分割后,改列拥有的数值数量,下面简称n

join过程的伪代码:

根据ID进行循环

{

判断:i 是否

{

获取最靠近第 i 个逗号之前的数据, 即 substring_index(substring_index(a.mSize,',',b.ID),',',-1)

i = i +1 

}

ID = ID +1 

}

总结:

这种方法的缺点在于,我们需要一个拥有连续数列的独立表(这里是incre_table)。并且连续数列的最大值一定要大于符合分割的值的个数。

例如有一行的mSize 有100个逗号分割的值,那么我们的incre_table 就需要有至少100个连续行。

当然,mysql内部也有现成的连续数列表可用。如mysql.help_topic: help_topic_id 共有504个数值,一般能满足于大部分需求了。

改写后如下:

复制代码
<span style="color:#00ff">select</span> a.ID,substring_index(substring_index(a.mSize,<span style="color:#ff00">'</span><span style="color:#ff00">,</span><span style="color:#ff00">'</span>,b.help_topic_id<span style="color:#808080">+</span><span style="color:#8000; font-weight:bold">1</span>),<span style="color:#ff00">'</span><span style="color:#ff00">,</span><span style="color:#ff00">'</span>,<span style="color:#808080">-</span><span style="color:#8000; font-weight:bold">1</span><span style="color:#000000">) 
</span><span style="color:#00ff">from</span><span style="color:#000000"> 
tbl_name a
</span><span style="color:#808080">join</span><span style="color:#000000">
mysql.help_topic b
</span><span style="color:#00ff">on</span> b.help_topic_id <span style="color:#808080"> (length(a.mSize) <span style="color:#808080">-</span> length(<span style="color:#ff0ff">replace</span>(a.mSize,<span style="color:#ff00">'</span><span style="color:#ff00">,</span><span style="color:#ff00">'</span>,<span style="color:#ff00">''</span>))<span style="color:#808080">+</span><span style="color:#8000; font-weight:bold">1</span><span style="color:#000000">)
</span><span style="color:#00ff">order</span> <span style="color:#00ff">by</span> a.ID;</span>
Copy after login
复制代码 测试实例:

Copy after login
Copy after login
Copy after login
-- SELECT  help_topic_id  FROM mysql.help_topic
-- eg.把一个字段用“,”分隔开组合
select group_concat(user_id ORDER BY user_id ASC) as nids from admin_user
SELECT b.did,GROUP_CONCAT(b.sid ORDER BY adjustment DESC,similar DESC) FROM test b GROUP BY b.did 


-- 1.如果多个导购同1张单的先分解
-- 加时间段
select a.DJBH,a.je,substring_index(substring_index(a.dgy_list_id,&#39;,&#39;,b.help_topic_id+1),&#39;,&#39;,-1) 
from 
ipos_qtlsd  a
join
mysql.help_topic b
on b.help_topic_id < (length(a.dgy_list_id) - length(replace(a.dgy_list_id,&#39;,&#39;,&#39;&#39;))+1) and a.djbh=&#39;BP0102_qtsy000070&#39;
order by a.DJBH;

-- 2.取平均值

-- SELECT  help_topic_id  FROM mysql.help_topic
-- 1.如果多个导购同1张单的先分解
-- @zddm
-- @ rq
select a.DJBH,
substring_index(substring_index(a.dgy_list_id,&#39;,&#39;,b.help_topic_id+1),&#39;,&#39;,-1) AS FJID,
substring_index(substring_index(a.dgy_list_mc,&#39;,&#39;,b.help_topic_id+1),&#39;,&#39;,-1) AS FJMC,
FORMAT(a.je/(length(a.dgy_list_id) - length(replace(a.dgy_list_id,&#39;,&#39;,&#39;&#39;))+1),2) AS FJJE,
je 
from 
ipos_qtlsd  a
join
mysql.help_topic b
on b.help_topic_id < (length(a.dgy_list_id) - length(replace(a.dgy_list_id,&#39;,&#39;,&#39;&#39;))+1) 
and a.rq BETWEEN UNIX_TIMESTAMP(&#39;2016-04-01&#39;) and UNIX_TIMESTAMP(&#39;2016-05-01&#39;)
and a.djbh=&#39;gd_151125000001&#39;
order by a.DJBH;

-- gd_151125000001 
--3.分解后的指标
-- SELECT  help_topic_id  FROM mysql.help_topic
-- 1.如果多个导购同1张单的先分解
-- @khdm_change 终端代码
-- @start_time 开始时间
-- @end_time  结束时间
-- SELECT * FROM ipos_qtlsd WHERE djbh=&#39;gd_151125000001&#39;
set @khdm_change =&#39;BP0102&#39;;
set @start_time=UNIX_TIMESTAMP(&#39;2016-04-01&#39;);
set @end_time=UNIX_TIMESTAMP(&#39;2016-05-01&#39;);
SELECT FJID,FJMC,SUM(FJJE) 
FROM(
select a.zddm,a.zdmc,a.DJBH,
 substring_index(substring_index(a.dgy_list_id,&#39;,&#39;,b.help_topic_id+1),&#39;,&#39;,-1) AS FJID,
 substring_index(substring_index(a.dgy_list_mc,&#39;,&#39;,b.help_topic_id+1),&#39;,&#39;,-1) AS FJMC,
 FORMAT(a.je/(length(a.dgy_list_id) - length(replace(a.dgy_list_id,&#39;,&#39;,&#39;&#39;))+1),2) AS FJJE,
 je 
from ipos_qtlsd  a
 join mysql.help_topic b on b.help_topic_id < (length(a.dgy_list_id) - length(replace(a.dgy_list_id,&#39;,&#39;,&#39;&#39;))+1) 
and a.rq BETWEEN  @start_time and @end_time
and a.zd_id=(SELECT id from com_base_kehu where khdm=@khdm_change)
) AA
GROUP BY FJID,FJMC
-- and a.djbh=&#39;gd_151125000001&#39;
-- order by a.DJBH;
Copy after login


Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot Article Tags

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

PHP's big data structure processing skills PHP's big data structure processing skills May 08, 2024 am 10:24 AM

PHP's big data structure processing skills

How to optimize MySQL query performance in PHP? How to optimize MySQL query performance in PHP? Jun 03, 2024 pm 08:11 PM

How to optimize MySQL query performance in PHP?

How to use MySQL backup and restore in PHP? How to use MySQL backup and restore in PHP? Jun 03, 2024 pm 12:19 PM

How to use MySQL backup and restore in PHP?

How to insert data into a MySQL table using PHP? How to insert data into a MySQL table using PHP? Jun 02, 2024 pm 02:26 PM

How to insert data into a MySQL table using PHP?

What are the application scenarios of Java enumeration types in databases? What are the application scenarios of Java enumeration types in databases? May 05, 2024 am 09:06 AM

What are the application scenarios of Java enumeration types in databases?

How to fix mysql_native_password not loaded errors on MySQL 8.4 How to fix mysql_native_password not loaded errors on MySQL 8.4 Dec 09, 2024 am 11:42 AM

How to fix mysql_native_password not loaded errors on MySQL 8.4

How to use MySQL stored procedures in PHP? How to use MySQL stored procedures in PHP? Jun 02, 2024 pm 02:13 PM

How to use MySQL stored procedures in PHP?

How to create a MySQL table using PHP? How to create a MySQL table using PHP? Jun 04, 2024 pm 01:57 PM

How to create a MySQL table using PHP?

See all articles