Useful SQL

mysql_tips.sql

ALTER TABLE forecast.workstream_data
ADD timezone VARCHAR(40);

-- Copying data - specific column from one table to another based on row condition
UPDATE forecast.workstream_data set timezone = (SELECT o.timezone FROM roster.organisation as o where o.id=workstream_data.organisation_id)
 WHERE user_id is NULL;

-- Copying data - specific column from one table to another based on row condition
UPDATE forecast.workstream_data set workstream_data.timezone = (
SELECT t.timezone
FROM roster.user as u, roster.team t
  WHERE  u.id=workstream_data.user_id
  AND u.team_id=t.id
);

-- Dump specific tables to SQL File
mysqldump -u db_user -p db_schema tableA tableB tableC > my_tables.sql

-- Another useful QUERY use `STR_TO_DATE`, `CONCAT`, `LPAD`, `IF`
SELECT
  date_format( ForecastQuarterHourVolume.start_time, '%Y-%m-%d %H:00:00') as start_timeNN,
  SUM(ForecastQuarterHourVolume.volume) as total_volume,
  ceil(AVG(ForecastQuarterHourVolume.average_handle_time)) as aht,
  SUM(ForecastQuarterHourVolume.volume) * AVG(ForecastQuarterHourVolume.average_handle_time) as workload
FROM
(
  -- Join Daily Forecast Data to Quarter Hour workload percent table to calculate Quarter Hour Volume
  SELECT
    STR_TO_DATE(CONCAT(DATE_FORMAT(start_time, '%Y-%m-%d'),
                       ' ',
                       LPAD(h.ws_hour, 2, '0'),
                       ':',
                       LPAD(h.ws_min, 2, '0')
                ), '%Y-%m-%d %H:%i')                                                 AS start_time,
    (IF(fp.adjusted_volume<0,0,fp.adjusted_volume) * h.daily_volume_percent)         AS volume,
    h.aht                                                                            AS average_handle_time,
    (IF(fp.adjusted_volume<0,0,fp.adjusted_volume) * h.daily_volume_percent * h.aht) AS workload,
    h.workstream_id                                                                  AS workstream_id

  FROM forecast_data.historical_workstream_percent AS h
    RIGHT JOIN forecast_data.forecast_point AS fp
      ON h.weekday_short = substring(DAYNAME(fp.start_time), 1, 3)
         AND h.workstream_id = fp.workstream_id
  WHERE h.ws_timezone = 'UTC'
        AND fp.published_forecast_id = 188
        AND fp.start_time >= '2017-10-01 00:00:00' AND fp.start_time <= '2017-10-18 00:00:00'
) as ForecastQuarterHourVolume
    GROUP BY DATE_FORMAT(ForecastQuarterHourVolume.start_time, '%Y-%m-%d %H')