<SPAN style=‘font: 16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; float: none; display: inline !important; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘>INSTR
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> (源字符串, 目标字符串, 起始位置, 匹配序号)
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> 在Oracle/PLSQL中，instr函数返回要截取的字符串在源字符串中的位置。只检索一次，就是说从字符的开始
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> 到字符的结尾就结束。
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> 语法如下：
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> instr( string1, string2 [, start_position [, nth_appearance ] ] )
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> 参数分析：
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> string1
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> 源字符串，要在此字符串中查找。
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> string2
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> 要在string1中查找的字符串.
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> start_position
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> 代表string1 的哪个位置开始查找。此参数可选，如果省略默认为1. 字符串索引从1开始。如果此参数为正，从左到右开始检索，如果此参数为负，从右到左检索，返回要查找的字符串在源字符串中的开始索引。
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> nth_appearance
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> 代表要查找第几次出现的string2. 此参数可选，如果省略，默认为 1.如果为负数系统会报错。
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> 注意：
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> 如果String2在String1中没有找到，instr函数返回0.
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> 示例：
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> SELECT instr(‘syranmo‘,‘s‘) FROM dual; -- 返回 1
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> SELECT instr(‘syranmo‘,‘ra‘) FROM dual; -- 返回 3
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> 1 SELECT instr(‘syran mo‘,‘a‘,1,2) FROM dual; -- 返回 0
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> （根据条件，由于a只出现一次，第四个参数2，就是说第2次出现a的位置，显然第2次是没有再出现了，所以结果返回0。注意空格也算一个字符！）
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> SELECT instr(‘syranmo‘,‘an‘,-1,1) FROM dual; -- 返回 4
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> （就算是由右到左数，索引的位置还是要看‘an’的左边第一个字母的位置，所以这里返回4）
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> SELECT instr(‘abc‘,‘d‘) FROM dual; -- 返回 0
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘> 注：也可利用此函数来检查String1中是否包含String2，如果返回0表示不包含，否则表示包含。
16px/28px "Hiragino Sans GB W3", "Hiragino Sans GB", Arial, Helvetica, simsun, u5b8bu4f53; margin: 0px 0px 10px; padding: 0px; text-align: left; color: rgb(51, 51, 51); text-transform: none; text-indent: 0px; letter-spacing: normal; word-spacing: 0px; white-space: normal; font-size-adjust: none; font-stretch: normal; background-color: rgb(255, 255, 255); -webkit-text-stroke-width: 0px;‘>
原文：http://www.cnblogs.com/rongfengliang/p/3718321.html
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