MySQL ã«éãããSQL ã®NULL ã®ä»æ§ã«ã¯ä½åãããã£ãã¨é©ããã¨ããã£ãã®ã§ã¡ã¢ãã¦ãããã¨æãã¾ãã5.1 çã®æ¥æ¬èªããã¥ã¢ã«ããªãã£ããã®ã«ã¤ãã¦ã¯ã4.1 ã®ããã¥ã¢ã«ãåç §ãã¾ããã ããããNULL ã¯ä½ãæå³ããã NULL ã¯æªå®ç¾©ã¾ãã¯ãä¸æãæå³ããããé»è©±çªå·ãæããªããã¨ãããã¨ã表ç¾ããå ´åã¯ãNULL ã§ã¯ãªãã空ã®æååã使ãã NULL å¤ã¨ãããã®ã SQL åå¿è ã¯ããæ··ä¹±ãã¾ããSQL åå¿è ã¯ãå¤ãã®å ´åãNULL ã空æå "" ã¨åãã§ããã¨èãã¦ãã¾ãã¾ããããã¯éãã¾ãããã¨ãã°ã以ä¸ã®ã¹ãã¼ãã¡ã³ãã¯å®å ¨ã«å¥ã®ãã®ã§ãã mysql> INSERT INTO my_table (phone) VALUES (NULL); mysql> INSERT INTO my_table (phone) VALUES (""); ã©ã¡ãã®ã¹
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