MySQL 8.0

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CREATE TABLE mytable2023 (id int, a varchar(10), b varchar(10), c varchar(10))
INSERT INTO mytable2023 VALUES (1,NULL,'B', NULL),(2,NULL,'B1', NULL)

Records: 2  Duplicates: 0  Warnings: 0


SELECT COLUMN_NAME
  FROM INFORMATION_SCHEMA.COLUMNS
  WHERE  TABLE_NAME = 'mytable2023'; #TABLE_SCHEMA = 'my_database' AND


COLUMN_NAME


a

b

c

id


CREATE PROCEDURE delcolumn(
	tbname varchar(100)
)
BEGIN
	DECLARE finished INTEGER DEFAULT 0;

	DECLARE colname varchar(100) DEFAULT "";

	-- declare cursor for employee email
	DEClARE curcol 
		CURSOR FOR 
			SELECT COLUMN_NAME
            FROM INFORMATION_SCHEMA.COLUMNS
            WHERE  TABLE_NAME = tbname; #TABLE_SCHEMA = 'my_database' AND

	-- declare NOT FOUND handler
	DECLARE CONTINUE HANDLER 
        FOR NOT FOUND SET finished = 1;

	OPEN curcol;

	getcol: LOOP
		FETCH curcol INTO colname;
		IF finished = 1 THEN 
			LEAVE getcol;
		END IF;
		-- build email list
		 SET @sql = CONCAT('SELECT COUNT(`',colname,'`) INTO @count FROM `',tbname,'`;');
         PREPARE stmt2 FROM @sql;
         EXECUTE stmt2;
       IF @count = 0 THEN
         SET @sql = CONCAT('ALTER TABLE `',tbname,'` DROP COLUMN `',colname,'`');
         PREPARE stmt2 FROM @sql;
         EXECUTE stmt2;
       END IF;
	END LOOP getcol;
	CLOSE curcol;

END
CALL delcolumn('mytable2023')
SELECT * FROM mytable2023


id
b


1
B

2
B1