Concatenated columns

Gives a column with concatenated column names for columns with "enabled" value. e.g., 'B1, B3' for the third row in the example below.

You must execute the code again to save those values in the database.

-- INIT database
CREATE TABLE SampleData (
  t_stamp DATE,
  B1 VARCHAR(20),
  B2 VARCHAR(20),
  B3 VARCHAR(20),
  B4 VARCHAR(20)
);

INSERT INTO SampleData(t_stamp, B1, B2, B3, B4) VALUES ('2025-04-22 00:00:00', 'enabled', 'emptied', 'not used', 'cutoff');
INSERT INTO SampleData(t_stamp, B1, B2, B3, B4) VALUES ('2025-04-22 01:00:00', 'do not use', 'emptied', 'not used', 'cutoff');
INSERT INTO SampleData(t_stamp, B1, B2, B3, B4) VALUES ('2025-04-22 02:00:00', 'enabled', 'emptied', 'enabled', 'cutoff');
INSERT INTO SampleData(t_stamp, B1, B2, B3, B4) VALUES ('2025-04-22 03:00:00', 'enabled', 'enabled', 'not used', 'enabled');

-- QUERY database
-- SELECT * FROM SampleData;
SELECT t_stamp,
	  CONCAT_WS("|", B1, B2, B3, B4) AS contents,
      IF(
           (IF(B1 = 'enabled', 1, 0) +
            IF(B2 = 'enabled', 1, 0) +
            IF(B3 = 'enabled', 1, 0) +
            IF(B4 = 'enabled', 1, 0)
            
        ) = 0,
        '-----',
        CONCAT_WS(
          ', ',
          IF(B1 = 'enabled', 'B1', NULL),
          IF(B2 = 'enabled', 'B2', NULL),
          IF(B3 = 'enabled', 'B3', NULL),
          IF(B4 = 'enabled', 'B4', NULL)
        )
      ) AS BinsEnabled
FROM SampleData;

t_stamp	contents	BinsEnabled
2025-04-22	enabled\|emptied\|not used\|cutoff	B1
2025-04-22	do not use\|emptied\|not used\|cutoff	-----
2025-04-22	enabled\|emptied\|enabled\|cutoff	B1, B3
2025-04-22	enabled\|enabled\|not used\|enabled	B1, B2, B4