本文基于转载:
lpad函数从左边对字符串使用指定的字符进行填充。lpad意思是从左边填充的意思。
语法格式如下:
lpad( string, padded_length, [ pad_string ] );
string :准备被填充的字符串;
padded_length:填充之后的字符串长度,也就是该函数返回的字符串长度,如果这个数量比原字符串的长度要短,lpad函数将会把字符串截取成从左到右的n个字符;
pad_string:填充字符串,是个可选参数,这个字符串是要粘贴到string的左边,如果这个参数未写,lpad函数将会在string的左边粘贴空格。
示例1:
select lpad('abcde',10,'x') from dual;
aaarticlea/png;base64,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" alt="" />
示例2:
select lpad('abcde',10,'oq') from dual;
aaarticlea/png;base64,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" alt="" />
示例3:
select lpad('abcde',2) from dual;
aaarticlea/png;base64,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" alt="" />
与lpad函数对应的是rpad函数,rpad函数从右边对字符串使用指定的字符进行填充,语法格式与lpad格式相同。