mysql, transpose/pivot row to column, variable selects

Question

Hello again and thank you in advance for your help.

I\'ve checked a few prior questions and couldn\'t find this exact situation.

I\'m trying to transpose/pi

Answer 1

SELECT  Install_DATE,
        MAX(CASE WHEN Install_DATE = '01-24-2013' THEN totalCount END) `01-24-2013`,
        MAX(CASE WHEN Install_DATE = '01-25-2013' THEN totalCount END) `01-25-2013`,
        MAX(CASE WHEN Install_DATE = '01-26-2013' THEN totalCount END) `01-26-2013`,
        .......
FROM
(
  SELECT DATE_FORMAT(packet_details.installDate,'%m-%d-%Y') as Install_Date,
         Count(packet_details.installDate) totalCount
  FROM   packet_details
  WHERE  packet_details.installDate >= CURRENT_DATE - INTERVAL 7 DAY AND 
         packet_details.installDate   < CURRENT_DATE + INTERVAL 7 DAY
  GROUP  BY installDate
) s

• SQLFiddle Demo

For unknown number of Install_Date, a Dynamic Query is much preferred,

SET @sql = NULL;
SELECT
  GROUP_CONCAT(DISTINCT
    CONCAT(
      'MAX(CASE WHEN Install_DATE = ''',
      Install_Date,
      ''' then totalCount end) AS `', Install_Date, '`' )
  ) INTO @sql
FROM 
(
  SELECT DATE_FORMAT(packet_details.installDate,'%m-%d-%Y') as Install_Date,
         Count(packet_details.installDate) totalCount
  FROM   packet_details
  WHERE  packet_details.installDate >= CURRENT_DATE - INTERVAL 7 DAY AND 
         packet_details.installDate   < CURRENT_DATE + INTERVAL 7 DAY
  GROUP  BY installDate
) s;

SET @sql = CONCAT('SELECT Install_DATE, ', @sql, ' 
                    FROM
                    (
                      SELECT DATE_FORMAT(packet_details.installDate,''%m-%d-%Y'') as Install_Date,
                             Count(packet_details.installDate) totalCount
                      FROM   packet_details
                      WHERE  packet_details.installDate >= CURRENT_DATE - INTERVAL 7 DAY AND 
                             packet_details.installDate   < CURRENT_DATE + INTERVAL 7 DAY
                      GROUP  BY installDate
                    ) s');

PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

• SQLFiddle Demo