MYSQL 删除一个字段前判断字段是否存在的办法

ALTER TABLE table_name DROP COLUMN IF EXISTS column_name;

--切换到指定的数据 根据自己的情况
use your_dbname;
-- 删除存储过程
DROP PROCEDURE IF EXISTS sp_delete_column_if_exists;
-- 创建存储过程
DELIMITER $$
CREATE PROCEDURE `sp_delete_column_if_exists`(
    IN `dbName` VARCHAR(255),
    IN `tableName` VARCHAR(255),
    IN `columnName` VARCHAR(255)
)
begin
    SET @stmt = NULL;
    SELECT
        COUNT(*) INTO @stmt
    FROM
        information_schema.columns
    WHERE
        table_schema = dbName
        AND table_name = tableName
        AND column_name = columnName;
     SELECT
        COUNT(*) 
    FROM
        information_schema.columns
    WHERE
        table_schema = dbName
        AND table_name = tableName
        AND column_name = columnName;
    IF @stmt > 0 THEN
        SET @drop_column = CONCAT('ALTER TABLE `', dbName, '`.`', tableName, '` DROP COLUMN `', columnName, '`;');
        PREPARE drop_column FROM @drop_column;
        EXECUTE drop_column;
        DEALLOCATE PREPARE drop_column;
    END IF;
END$$
DELIMITER ;
-- 调用存储过程
call sp_delete_column_if_exists('your_db', 'your_table' , 'your_column');

delete from table where id='1'

delete from table