CODEWITHSUNDEEP
mysqlsqlgroup-concat
Dipak
Dipak

Reputation: 939

CONCAT within GROUP_CONCAT - How to remove duplicate result

CONCAT within GROUP_CONCAT, what is wrong with following mysql code ? Please see SQL Fiddle, full code is there.

Let me explain, I have 5 table

cls - List of Classes

sec - List of Sections

fee - List of Fee

cls_sec - List of section assigned to each class

cls_fee - List of fee assigned to each section

Table cls - lists of Class

id  |   ttl
===========
1   |   One
2   |   Two
3   |   Three

Table sec - lists of section

id  |   ttl
===========
1   |   A
2   |   B

Table cls_sec - lists of each section assigned to Class

id  |   c_id|   s_id    
=====================
1   |   1   |   1
2   |   1   |   2
3   |   2   |   1

Table fee - lists of fee category

id  |   ttl
===========
1   |   Annual
2   |   Monthly
3   |   Library

Table cls_fee - lists of each fee and amount assigned to Class

id  |   c_id|   s_id|   f_id|   fee 
=====================================
1   |   1   |   1   |   1   |    2000
2   |   1   |   1   |   2   |    500
3   |   1   |   2   |   1   |    3000
4   |   1   |   2   |   2   |    400
5   |   2   |   1   |   1   |    4500
6   |   2   |   1   |   2   |    450
7   |   3   |   0   |   1   |    5000
8   |   3   |   0   |   2   |    600
9   |   3   |   0   |   3   |    300

Here I am trying to include all relation in one GROUP_CONCAT Result

My current output (Class name and section name is fetched repetitively according to fee )

//Class Name - Section Name (if exist) - fee, Class Name - Section Name (if exist) - fee ..

3.Three.Library->300, 3.Three.Monthly->600, 3.Three.Annual->5000, 
2.Two-A.Monthly->450, 2.Two-A.Annual->4500, 1.One-A.Monthly->500, 
1.One-A.Annual->2000, 1.One-B.Monthly->400, 1.One-B.Annual->3000

with following code

  GROUP_CONCAT(DISTINCT CONCAT('\r\n',cls.id,'.',cls.ttl,
       COALESCE(CONCAT('-',sec.ttl),''),COALESCE(CONCAT('.',fee.ttl,'->',cls_fee.fee))) 
       ORDER BY sec.id) AS cls

But what I want (remove duplication class and section)

//Class Name - Section Name (if exists) - fee, fee

3.Three.Library->300,Monthly->600,Annual->5000, 
2.Two-A.Monthly->450,Annual->4500, 
1.One-A.Monthly->500,Annual->2000,
1.One-B.Monthly->400,Annual->3000

So I add CONCAT within nested CONCAT

  GROUP_CONCAT(DISTINCT CONCAT('\r\n',cls.id,'.',cls.ttl,
      COALESCE(CONCAT('-',sec.ttl,COALESCE(CONCAT('.',fee.ttl,'->',cls_fee.fee))), '')) 
      ORDER BY sec.id) AS cls

and got output, but it doesn't fetch as expected, also missing some fee

3.Three,
2.Two-A.Monthly->450, 2.Two-A.Annual->4500, 
1.One-A.Monthly->500, 1.One-A.Annual->2000, 
1.One-B.Monthly->400, 1.One-B.Annual->3000

MySQL CODE

SELECT
  GROUP_CONCAT(DISTINCT CONCAT('\r\n',cls.id,'.',cls.ttl,
      COALESCE(CONCAT('-',sec.ttl),''),COALESCE(CONCAT('.',fee.ttl,'->',cls_fee.fee))) 
      ORDER BY sec.id) AS cls
FROM
  cls
LEFT JOIN
  cls_sec ON cls_sec.cls = cls.id
LEFT JOIN
  sec ON sec.id = cls_sec.sec
LEFT JOIN
  cls_fee ON cls_fee.c_id = cls.id
LEFT JOIN
  fee ON fee.id = cls_fee.f_id
WHERE
  CASE WHEN cls_fee.s_id != 0 THEN cls_fee.s_id = sec.id ELSE cls.id END

SQL Fiddle

Upvotes: 1

Views: 219

Answers (1)

D-Shih
D-Shih

Reputation: 46219

You can try to use a subquery to write GROUP_CONCAT from detail by cls.id, cls.ttl then do GROUP_CONCAT again in the main query.

Query 1:

SELECT GROUP_CONCAT(CONCAT(Id,'.',ttl,'.',flag,cls)  ORDER BY Id desc,flag) result
FROM (
  SELECT
     cls.id,
     cls.ttl,
     COALESCE(CONCAT('-',sec.ttl),'') flag,
     GROUP_CONCAT(DISTINCT CONCAT(
                COALESCE(CONCAT('.',fee.ttl,'->',cls_fee.fee))) 
                ORDER BY sec.id) AS cls
  FROM
    cls
  LEFT JOIN
    cls_sec ON cls_sec.cls = cls.id
  LEFT JOIN
    sec ON sec.id = cls_sec.sec
  LEFT JOIN
    cls_fee ON cls_fee.c_id = cls.id
  LEFT JOIN
    fee ON fee.id = cls_fee.f_id
  WHERE
    CASE WHEN cls_fee.s_id != 0 THEN cls_fee.s_id = sec.id ELSE cls.id END
  GROUP BY 
     cls.id,
     cls.ttl,
     COALESCE(CONCAT('-',sec.ttl),'')
)t1

Results:

|                                                                                                                                                        result |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 3.Three..Library->300,.Monthly->600,.Annual->5000,2.Two.-A.Monthly->450,.Annual->4500,1.One.-A.Monthly->500,.Annual->2000,1.One.-B.Monthly->400,.Annual->3000 |

Upvotes: 1

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