MySQL Dynamic Pivot

SET SESSION group_concat_max_len = 1000000; -- Set a larger limit

SET @sql = NULL;
SELECT
  GROUP_CONCAT(DISTINCT
    CONCAT(
      'max(case when sales_week = ''',
      sales_week,
      ''' then sales_amount end) AS `',
      sales_week, '`'
    )
  ) INTO @sql
FROM
  test_table;
SET @sql = CONCAT('SELECT seller, ', @sql, '
                  FROM test_table
                  GROUP BY seller');

-- SELECT @sql;

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