嵌套连接查询

Question

I have a SQL query:

SELECT  a.LAN_ABBR, a.COUNTRY, a.CITY, a.SITE, a.Address,
        c.Network_Priority, c.Dedicated_Network, c.Other_Network,
        c.LAN_One, c.LAN_two, c.LAN_three,
        c.LAN_four, c.LAN_five, c.LAN_six, c.LAN_seven,
        b.Remark
    FROM  server_data a
    LEFT OUTER JOIN  site_remark b  ON a.SITE = b.SITE_ABBR
    INNER JOIN       lan_service c  ON a.LAN_ABBR = c.LAN;

This Query is giving me output:

LAN_ABBR || COUNTRY || CITY || SITE || Address || Network_Priority || Dedicated_Network || Other_Network || LAN_One|| LAN_two || LAN_three || LAN_four || LAN_five || LAN_six || LAN_seven || Remark
==================================================================================================================================================================================================================
ABC1     || India   || Delhi|| XYZ1 || Delhi 1 || yes              || no                || no            || yes    || no      || yes       || yes      || yes      || no      || no        || Delhi Network 1 
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
ABC2     || India   || Delhi|| XYZ1 || Delhi 1 || no               || no                || yes           || no     || yes     || no        || no       || no       || yes     || no        || Delhi Network 1 
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
ABC3     || India   || Delhi|| XYZ1 || Delhi 1 || yes              || no                || no            || yes    || no      || no        || no       || no       || no      || no        || Delhi Network 1 
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
ABC4     || India   || Delhi|| XYZ2 || Delhi 1 || yes              || no                || yes           || no     || yes     || no        || no       || no       || yes     || yes       || Delhi Network 4 
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------    

I want a result which looks like:

 COUNTRY || CITY || SITE || Address || Network_Priority || Dedicated_Network || Other_Network || LAN_One|| LAN_two || LAN_three || LAN_four || LAN_five || LAN_six || LAN_seven || Remark
==================================================================================================================================================================================================================
 India   || Delhi|| XYZ1 || Delhi 1 || yes              || no                || yes           || yes    || yes     || yes       || yes      || yes      || yes     || no        || Delhi Network 1 
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

 India   || Delhi|| XYZ2 || Delhi 1 || yes              || no                || yes           || no     || yes     || no        || no       || no       || yes     || yes       || Delhi Network 4 
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------    

Logic:

If a.Site has a duplicate entry 

{

check(

c.Network_Priority (Single entry for yes no: If even single "yes" then complete "yes" else "no"), 

c.Dedicated_Network (Single entry for yes no: If even single "yes" then complete "yes" else "no"), 

c.Other_Network (Single entry for yes no: If even single "yes" then complete "yes" else "no"), 

c.LAN_One (Single entry for yes no: If even single "yes" then complete "yes" else "no"), 

c.LAN_two (Single entry for yes no: If even single "yes" then complete "yes" else "no"), 

c.LAN_three (Single entry for yes no: If even single "yes" then complete "yes" else "no"), 

c.LAN_four (Single entry for yes no: If even single "yes" then complete "yes" else "no"), 

c.LAN_five (Single entry for yes no: If even single "yes" then complete "yes" else "no"), 

c.LAN_six (Single entry for yes no: If even single "yes" then complete "yes" else "no"), 

c.LAN_seven (Single entry for yes no: If even single "yes" then complete "yes" else "no"),

} 

Answer 1

You can try to use MAX and MIN function to get your expect result.

SELECT  a.COUNTRY, 
        a.CITY, 
        a.SITE, 
        a.Address, 
        MAX(c.Network_Priority), 
        MAX(c.Dedicated_Network), 
        MAX(c.Other_Network), 
        MAX(c.LAN_One),
        MAX(c.LAN_two), 
        MAX(c.LAN_three), 
        MAX(c.LAN_four), 
        MAX(c.LAN_five), 
        MAX(c.LAN_six), 
        MAX(c.LAN_seven), 
        MIN(b.Remark) Remark
FROM server_data a 
LEFT OUTER JOIN site_remark b ON a.SITE = b.SITE_ABBR 
INNER JOIN lan_service c ON a.LAN_ABBR = c.LAN
GROUP BY a.COUNTRY,a.CITY,a.SITE,a.Address

Here is a simple

CREATE TABLE T(
  LAN_ABBR VARCHAR(50), 
  COUNTRY VARCHAR(50), 
  CITY VARCHAR(50), 
  SITE VARCHAR(50), 
  Address  VARCHAR(50), 
  Network_Priority  VARCHAR(50), 
  Dedicated_Network  VARCHAR(50), 
  Other_Network  VARCHAR(50), 
  LAN_One VARCHAR(50),
  LAN_two  VARCHAR(50), 
  LAN_three  VARCHAR(50), 
  LAN_four  VARCHAR(50), 
  LAN_five  VARCHAR(50),
  LAN_six  VARCHAR(50),
  LAN_seven  VARCHAR(50), 
  Remark VARCHAR(50)
);

INSERT INTO T VALUES ('ABC1','India','Delhi','XYZ1','Delhi 1','yes','no','no','yes','no','yes','yes','yes','no','no','Delhi Network 1'); 
INSERT INTO T VALUES ('ABC2','India','Delhi','XYZ1','Delhi 1','no','no','yes','no','yes','no','no','no','yes','no','Delhi Network 1'); 
INSERT INTO T VALUES ('ABC3','India','Delhi','XYZ1','Delhi 1','yes','no','no','yes','no','no','no','no','no','no','Delhi Network 1'); 
INSERT INTO T VALUES ('ABC4','India','Delhi','XYZ2','Delhi 1','yes','no','yes','no','yes','no','no','no','yes','yes','Delhi Network 4'); 

Query 1 :

SELECT  COUNTRY, 
        CITY, 
        SITE, 
        Address, 
        MAX(Network_Priority) Network_Priority, 
        MAX(Dedicated_Network) Dedicated_Network, 
        MAX(Other_Network) Other_Network, 
        MAX(LAN_One) LAN_One,
        MAX(LAN_two) LAN_two, 
        MAX(LAN_three) LAN_three, 
        MAX(LAN_four) LAN_four, 
        MAX(LAN_five) LAN_five, 
        MAX(LAN_six) LAN_six, 
        MAX(LAN_seven) LAN_seven, 
        MIN(Remark) Remark 
FROM T
GROUP BY COUNTRY,CITY,SITE,Address

Results :

| COUNTRY |  CITY | SITE | Address | Network_Priority | Dedicated_Network | Other_Network | LAN_One | LAN_two | LAN_three | LAN_four | LAN_five | LAN_six | LAN_seven |          Remark |
|---------|-------|------|---------|------------------|-------------------|---------------|---------|---------|-----------|----------|----------|---------|-----------|-----------------|
|   India | Delhi | XYZ1 | Delhi 1 |              yes |                no |           yes |     yes |     yes |       yes |      yes |      yes |     yes |        no | Delhi Network 1 |
|   India | Delhi | XYZ2 | Delhi 1 |              yes |                no |           yes |      no |     yes |        no |       no |       no |     yes |       yes | Delhi Network 4 |

NOTE

this query assumes there is only three two type in your columns 'yes' or 'no' .

If there are other states in your columns,you can try to use condition aggregate function

SELECT  COUNTRY, 
        CITY, 
        SITE, 
        Address, 
        MAX(Network_Priority) Network_Priority, 
        MAX(CASE WHEN Dedicated_Network='yes' then 'yes' else 'no' end) Dedicated_Network, 
        MAX(CASE WHEN Other_Network='yes' then 'yes' else 'no' end) Other_Network, 
        MAX(CASE WHEN LAN_One='yes' then 'yes' else 'no' end) LAN_One,
        MAX(CASE WHEN LAN_two='yes' then 'yes' else 'no' end) LAN_two, 
        MAX(CASE WHEN LAN_three='yes' then 'yes' else 'no' end) LAN_three, 
        MAX(CASE WHEN LAN_four='yes' then 'yes' else 'no' end) LAN_four, 
        MAX(CASE WHEN LAN_five='yes' then 'yes' else 'no' end) LAN_five, 
        MAX(CASE WHEN LAN_six='yes' then 'yes' else 'no' end) LAN_six, 
        MAX(CASE WHEN LAN_seven='yes' then 'yes' else 'no' end) LAN_seven, 
        MIN(Remark) Remark 
FROM T
GROUP BY COUNTRY,CITY,SITE,Address

Answer 2

You may use the following with grouping by a.COUNTRY, a.CITY, a.SITE, a.Address, b.Remark , and use max() for related cases as follows :

SELECT a.COUNTRY, a.CITY, a.SITE, a.Address, 
       (case when max(c.Network_Priority)='yes' then
        else 'no'
        end) as Network_Priority, 
       (case when max(c.Dedicated_Network)='yes' then
        else 'no'
        end) as Dedicated_Network,
       (case when max(c.Other_Network)='yes' then
        else 'no'
        end) as Other_Network,
       (case when max(c.LAN_one)='yes' then
        else 'no'
        end) as LAN_one,
       (case when max(c.LAN_two)='yes' then
        else 'no'
        end) as LAN_two,
       (case when max(c.LAN_three)='yes' then
        else 'no'
        end) as LAN_three,
       (case when max(c.LAN_four)='yes' then
        else 'no'
        end) as LAN_four,
       (case when max(c.LAN_five)='yes' then
        else 'no'
        end) as LAN_five,
       (case when max(c.LAN_six)='yes' then
        else 'no'
        end) as LAN_six,
       (case when max(c.LAN_seven)='yes' then
        else 'no'
        end) as c.LAN_seven,
       b.Remark
  FROM server_data a 
  LEFT OUTER JOIN site_remark b 
    ON a.SITE = b.SITE_ABBR 
 INNER JOIN lan_service c 
    ON a.LAN_ABBR = c.LAN
GROUP BY a.COUNTRY, a.CITY, a.SITE, a.Address, b.Remark;