1. 创建替换函数
   以下函数取自网上版本，暂时没细研究

SET GLOBAL log_bin_trust_function_creators=1;
DROP FUNCTION IF EXISTS fnStripTags;
DELIMITER |
CREATE FUNCTION fnStripTags( Dirty text(0) )
RETURNS text(0)
DETERMINISTIC 
BEGIN
  DECLARE iStart, iEnd, iLength int;
    WHILE Locate( '<', Dirty ) > 0 And Locate( '>', Dirty, Locate( '<', Dirty )) > 0 DO
      BEGIN
        SET iStart = Locate( '<', Dirty ), iEnd = Locate( '>', Dirty, Locate('<', Dirty ));
        SET iLength = ( iEnd - iStart) + 1;
        IF iLength > 0 THEN
          BEGIN
            SET Dirty = Insert( Dirty, iStart, iLength, '');
          END;
        END IF;
      END;
    END WHILE;
    RETURN Dirty;
END;
|
DELIMITER ;

2. 执行

select fnStripTags(content);
#如果需要保留换行，可先替换br为\r\n
select fnStripTags(replace(content,'<br />','\r\n'))