PostgreSQL 7.2.3 �桼��
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5.4. �ؿ�

�ؿ��ƤӽФ��ΰ��ϰʲ��μ��˽��äƲ�褵��ޤ��

�ؿ��ΰ��β��

pg_proc ��ƥ५��ǰ��פ��뤫�ɤ��ޤ��unknown��ޤ��硢��ʳ��Ф򸫤Ĥ��뤳�ȤϤ��ޤ��ˡ�
��Τ˰��פ��Τ�¸�ߤ��ʤ��ä��硢��δؿ��ƤӽФ��ʿ�ޤʷ��׵�Ȥ��ƤΤ�Τ��ǧ��ޤ��ϡ��ؿ��ƤӽФ�� 1 �Ĥΰ��Ȥꡢ�ؿ�̾��餫�Υǡ��(��Ū��)̾��Ʊ��Ǥ��ȯ��ޤ��ˡ��δؿ��ΰ��ϡ�unknown��Υ�ƥ�뤫��ꤵ�줿�ǡ��ȥХ��ʥ�ߴ��Ǥʤ��Фʤ�ޤ��󡣤��ξ��˹礦��硢��Ū�ʴؿ��ƤӽФ��Ȥʤ��ؿ��ΰ��ϻ��ꤵ�줿�ǡ��˶��ޤ��
�Ǥ�褯�礦��Τ򸡺��ޤ��
1. ��Ϸ��礦��⤷��Ϲ礦�褦�˷��Ǥ��롢Ʊ��̾��İ��ο��Ʊ��ؿ��Τ��٤Ƥΰ��ޤ��unknown��ƥ��Ϥ��Ū�Ǥϲ��ˤǤⷿ��Ǥ��Ȥߤʤ��ޤ��ˡ��⤷1�Ĥ��ʤ��Ф��Ȥ��ޤ��Ǥʤ��м��ʳ��˿ʤߤޤ��
2. ��٤Ƥθ��򸡺��Ϸ��˺Ǥ��Τ˹礦��Τ�Ĥ��ޤ��Τ˹礦��Τ��ʤ��Ф��٤Ƥθ��Ĥ��ޤ��1�Ĥ��䤬�Ĥä��Ϥ��Ȥ��ޤ��ʳ��ξ��ϼ��ʳ��˿ʤߤޤ��
3. ��٤Ƥθ��򸡺��Ϸ��˺Ǥ��Τ˹礦��⤷��ϥХ��ʥ�ߴ��Τ��Τ�Ĥ��ޤ��⤷��Τ˹礦��Τ��Х��ʥ�ߴ��Τ��Τ��ʤ��Ф��٤Ƥθ��Ĥ��ޤ��1�Ĥθ��䤷��Ĥ�ʤ��硢��Ȥ��ޤ��ʳ��ξ��ϼ��ʳ��˿ʤߤޤ��
4. ��٤Ƥθ��򸡺��׵ᤵ��Ǥ�¿��ΰ��֤ǹ��ޤ��Τ�Ĥ��ޤ��ޤ��Τ��ʤ��Ф��٤Ƥθ��Ĥ��ޤ��1�Ĥθ��䤷��Ĥ�ʤ��硢��Ȥ��ޤ��ʳ��ξ��ϼ��ʳ��˿ʤߤޤ��
5. ��ϰ��unknown�Τ�Τ��ä��硢��λĤä��˰��֤Ǽ��뷿��ƥ��å��ޤ��⤷��Υ��ƥ��䤬��ä��硢��줾��Υݥ��ʸ����ƥ��򤷤ޤ��unknown��Υ�ƥ��ϳΤ��ʸ��Τ褦�˸��Τǡ��ʸ��ؤΥХ��Ŭ��Ƥ��ޤ��ˡ��Ǥʤ��С��⤷�Ĥä��٤Ƥθ��䤬Ʊ��ƥ��Ϥ��Υ��ƥ��򤷤ޤ��Ǥ�ʤ��м��Ԥ��ޤ��ʤ��ʤ餵��˼�ݤ꤬�ʤ��򤬱��褵��뤳�Ȥ��Ǥ��ʤ��Ǥ��ˡ��ǡ��򤵤줿��ƥ��ǹ��ޤ��Τ��뤫�ɤ��դ��ޤ��򤵤줿��ƥ��ʤ��ϼΤƤޤ��ˡ��⤷��ǹ��ޤ��Ϳ��줿��ݥ��Ǽ��Τ��С��ΰ��ι��ޤ��ʤ��ΤƤޤ��
6. 1�Ĥθ��䤷��Ĥ�ʤ��硢��Ȥ��ޤ��⤷��䤬�ʤ��⤷��1�Ĥ��¿��䤬�Ĥ��ϼ��Ԥ��ޤ��

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Example 5-4. ��ؿ��ΰ��β��

pg_proc ��ˤϡ�int4fac �ؿ��1�ĤΤ��Ƥ��ޤ��Ǥ��顢��䤤��碌�ϼ�ưŪ�� int2��int4��Ѵ��ޤ��

tgl=> SELECT int4fac(int2 '4');
 int4fac
---------
      24
(1 row)

��ơ��ºݤˤϥѡ��ˤ�äưʲ��Τ褦��Ѵ��ޤ��

tgl=> SELECT int4fac(int4(int2 '4'));
 int4fac
---------
      24
(1 row)

Example 5-5. ��ʬʸ��ؿ��ΰ��β��

pg_proc�ˤ�2�Ĥ�substr�ؿ��Ƥ��ޤ��text��int4��Ȥ��2 �Ĥΰ��Ĥ�Τ�1�Ĥ��ޤ��

��Τʤ�ʸ��Ϳ��ƸƤӽФ��硢��η��ϡ�1�Ĥθ��ؿ��η��ˤ��Ŭ�礷�ޤ��

tgl=> SELECT substr('1234', 3);
 substr
--------
     34
(1 row)

��ơ��֥뤫��ʸ��Ȥ��ä��ˤ��ΤȤ��ơ�ʸ�� varchar��Ȥ��Ƥ��ˡ��ѡ��ʸ�� text��˶��褦�Ȥ��Ȥ��Τ��ޤ��

tgl=> SELECT substr(varchar '1234', 3);
 substr
--------
     34
(1 row)

�嵭�Τ�Τϡ��ѡ��ˤ�äƼ��Τ褦��Ѵ��ޤ��

tgl=> SELECT substr(text(varchar '1234'), 3);
 substr
--------
     34
(1 row)

Note: �ºݤˡ��ѡ��text��varchar���Х��ʥ�ߴ���Ȥ��Ȥ��ΤäƤ��ޤ��Ĥޤꡢʪ��Ū�Ѵ��Ԥ鷺�ˤ⤦��ؿ��Ϥ��뤳�Ȥ��Ǥ��Ȥ��ȤǤ��äƤ��ξ�硢��Ū�ʷ��Ѵ��ƤӽФ��ϼºݤˤ��ޤ��

int4��ȤäƸƤӽФ��줿��硢�ѡ��text ��Ѵ��褦�Ȥ��ޤ��

tgl=> SELECT substr(1234, 3);
 substr
--------
     34
(1 row)

�嵭�Τ�Τϡ��ºݤˤϼ��Τ褦�ˤʤ�ޤ��

tgl=> SELECT substr(text(1234), 3);
 substr
--------
     34
(1 row)

��ƥ५��text(int4)�Ȥ��Ѵ��ؿ��Τǡ��ޤ��

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