MySQL 语句级避免重复插入—— Insert Select Not Exist

INSERT INTO table(column1,column2,column3 ...columnN)
SELECT value1,value2,value3 ...valueN
FROM dual
WHERE NOT EXISTS(
      SELECT *
      FROM table
      WHERE value = ?
);

            INSERT INTO content (
                detail,
                status,
                beginTime,
                endTime) 
            SELECT
                @detail,
                1,
                NULL,
                NULL
            FROM DUAL
             WHERE NOT EXISTS(
                 SELECT contentId 
                 FROM content 
                 WHERE detail=@detail);