SUBSTR関数ã?¯æ–‡å—列å¼?ã?‚ã‚‹ã?„ã?¯ãƒ“ット列å¼?ã?«ä½œç”¨ã?—ã?¾ã?™ã€‚ çµ?æžœã?®ãƒ‡ãƒ¼ã‚¿åž‹ã?¯ã??れã?žã‚Œã€?å‰?者ã?®å ´å?ˆã?¯VARCHARã?§ã€?後者ã?®å ´å?ˆã?¯VARCHAR FOR BIT DATAã?§ã?™ã€‚ çµ?æžœã?®æœ€å¤§é•·ã?¯å…ƒã?®å¼•æ•°ã?®åž‹ã?®æœ€å¤§é•·ã?§ã?™ã€‚
SUBSTR({ æ–‡å—å¼? }, é–‹å§‹ä½?ç½® [, 列ã?®é•·ã?• ] )
引数ã?®é–‹å§‹ä½?ç½®ã?¨çœ?ç•¥å?¯èƒ½ã?ªåˆ—ã?®é•·ã?•ã?¯ã?©ã?¡ã‚‰ã‚‚æ•´æ•°å¼?ã?§ã?™ã€‚ å…ˆé ã?®æ–‡å—ã?‚ã‚‹ã?„ã?¯ãƒ“ットã?®é–‹å§‹ä½?ç½®ã?¯1ã?§ã?™ã€‚ ã‚‚ã?—0ã?Œä¸Žã?ˆã‚‰ã‚Œã?Ÿå ´å?ˆã€?Derbyã?¯1ã?Œä¸Žã?ˆã‚‰ã‚Œã?Ÿã‚‚ã?®ã?¨ã?¿ã?ªã?—ã?¾ã?™ã€‚
æ–‡å—å¼?ã?®ãƒ‡ãƒ¼ã‚¿åž‹ã?¯CHARã€?VARCHARã€?LONG VARCHARã€?ã?‚ã‚‹ã?„ã?¯(ビットå¼?ã?§ã?¯ã?ªã?„)æ–‡å—列ã?«æš—é»™ã?®ã?†ã?¡ã?«å¤‰æ?›å?¯èƒ½ã?ªçµ„ã?¿è¾¼ã?¿åž‹ã?®ä½•れã?‹ã?§ã?™ã€‚
æ–‡å—å¼?ã?§ã?¯é–‹å§‹ä½?ç½®ã?Šã‚ˆã?³åˆ—ã?®é•·ã?•ã?¨ã?„ã?†ãƒ‘ラメータã?¯æ–‡å—ã‚’ã?•ã?—ã?¾ã?™ã€‚ビットå¼?ã?«ã?¤ã?„ã?¦ã?¯ã€?é–‹å§‹ä½?ç½®ã?Šã‚ˆã?³åˆ—ã?®é•·ã?•ã?¨ã?„ã?†ãƒ‘ラメータã?¯ãƒ“ットをã?•ã?—ã?¾ã?™ã€‚
ã‚‚ã?—é–‹å§‹ä½?ç½®ã?Œæ£ã?§ã?‚れã?°ã€?ã??ã?®æ•°ã?¯åŸºã?¨ã?ªã‚‹å¼?ã?®å…ˆé ã?‹ã‚‰æ•°ã?ˆã?Ÿä½?置を指ã?—ã?¾ã?™ã€‚(å…ˆé ã?®æ–‡å—ã?¯1ã?¨æ•°ã?ˆã?¾ã?™ã€‚)é–‹å§‹ä½?ç½®ã?¯è² ã?¨ã?™ã‚‹ã?“ã?¨ã?Œã?§ã??ã?¾ã?›ã‚“。
ã‚‚ã?—列ã?®é•·ã?•ã?ŒæŒ‡å®šã?•れã?ªã?‹ã?£ã?Ÿå ´å?ˆã€?SUBSTRã?¯å¼?ã?®é–‹å§‹ä½?ç½®ã?‹ã‚‰æœ«å°¾ã?¾ã?§ã?®éƒ¨åˆ†åˆ—ã‚’è¿”ã?—ã?¾ã?™ã€‚ã‚‚ã?—列ã?®é•·ã?•ã?ŒæŒ‡å®šã?•れã?Ÿå ´å?ˆã€?SUBSTRã?¯é–‹å§‹ä½?ç½®ã?‹ã‚‰å§‹ã?¾ã‚‹åˆ—ã?®é•·ã?•ã?®ã€?VARCHARã?‚ã‚‹ã?„ã?¯VARBITã‚’è¿”ã?—ã?¾ã?™ã€‚ ã‚‚ã?—列ã?®é•·ã?•ã?«è² ã?®æ•°ã?Œä¸Žã?ˆã‚‰ã‚Œã?Ÿå ´å?ˆã€?SUBSTR関数ã?¯ã‚¨ãƒ©ãƒ¼ã‚’è¿”ã?—ã?¾ã?™ã€‚
VALUES SUBSTR('hello', 2)�果�'ello'��り��。
VALUES SUBSTR('hello',1,2)�果�'he'��り��。