1、拼接字符串
1)可以使用“||”来拼接字符串
select \'拼接\'||\'字符串\' as str from dual
2)通过concat()函数实现
select concat(\'拼接\', \'字符串\') as str from dual
注:oracle的concat函数只支持两个参数的方法,即只能拼接两个参数,如要拼接多个参数则嵌套使用concat可实现,如:
select concat(concat(\'拼接\', \'多个\'), \'字符串\') from dual
2、截取字符串
SUBSTR(string,start_position,[length]) 求子字符串,返回字符串
解释:string 源字符串
start_position 开始位置(从0开始)
length 可选项,子字符串的个数
select substr(to_char(sysdate, \'yyyy-mm-dd HH:mi:ss\'), 12, 5) as time from dual
substr("ABCDEFG", 0); //返回:ABCDEFG,截取所有字符 substr("ABCDEFG", 2); //返回:CDEFG,截取从C开始之后所有字符 substr("ABCDEFG", 0, 3); //返回:ABC,截取从A开始3个字符 substr("ABCDEFG", 0, 100); //返回:ABCDEFG,100虽然超出预处理的字符串最长度,但不会影响返回结果,系统按预处理字符串最大数量返回。 substr("ABCDEFG", -3); //返回:EFG,注意参数-3,为负值时表示从尾部开始算起,字符串排列位置不变。
字符串 "AAA-BBB" 截取"AAA" "BBB"
select substr(\'AAA-BBB\',1,instr(\'AAA-BBB\',\'-\',-1)-1) 值 from dual;
select substr(\'AAA-BBB\',instr(\'AAA-BBB\',\'-\',-1)+1) 值 from dual;
3、查找字符串
INSTR(string,subString,position,ocurrence)查找字符串位置
解释:string:源字符串
subString:要查找的子字符串
position:查找的开始位置
ocurrence:源字符串中第几次出现的子字符串
select INSTR(\'CORPORATE FLOOR\',\'OR\', 3, 2) as loc from dual
4、替换字符串
replace(strSource, str1, str2) 将strSource中的str1替换成str2
解析:strSource:源字符串
str1: 要替换的字符串
str2: 替换后的字符串
select \'替换字符串\' as oldStr, replace(\'替换字符串\', \'替换\', \'修改\') as newStr from dual
5、长度
length(nvl(字段,\'\'))=1
6、判断
SELECT SBXH, SFZJHM, case when length(nvl(XM,\'\'))=1 then XM when length(nvl(XM,\'\'))=2 then substr(XM, 0, 1)||\'*\' when length(nvl(XM,\'\'))=3 then substr(XM, 0, 1)||\'**\' when length(nvl(XM,\'\'))=4 then substr(XM, 0, 1)||\'***\' else substr(XM, 0, 1)||\'****\' end XM, DJXH, SDNF, DWMC, YNSE FROM ZHZS_SEWSR T WHERE YNSE > 120000.000000 AND DWMC IS NOT NULL AND SFZJHM LIKE \'36%\' ORDER BY YNSE DESC
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