**基本用法** ```sql SELECT LENGTH('Hello, World!') AS length_of_string FROM dual; ``` 这将返回 `13`,因为字符串 `'Hello, World!'` 包含 13 个字符。 2. **指定字符集** 假设你有一个包含多字节字符的字符串(例如中文),并且你想计算这些字符的数量。如果字符集支持多字节字符,你可以通过...
SELECT LENGTH('Hello World') AS LengthOfString FROM dual;输出：LengthOfString 11 示例2：计算字段的长度 SELECT LENGTH(first_name) AS LengthOfFirstName FROM employees;输出：LengthOfFirstName 5 6 3 ...示例3：计算CLOB字段的长度 SELECT LENGTH(clob_column) AS LengthOfClob FROM my_table;输出：Len...
--Count the length of stringselectlengthb('select * from scott.emp')ascountted_by_byte, length('select * from scott.emp')ascountted_by_charfromdual;--For some character encoding, the length() and the lengthb() is same in english--you may use this feature to check whether the string ...
DECLARE v_string VARCHAR2(50) := 'Hello World'; v_length NUMBER; BEGIN EXECUTE IMMEDIATE 'SELECT LENGTH(:1) FROM DUAL' INTO v_length USING v_string; DBMS_OUTPUT.PUT_LINE('Length of the string: ' || v_length); END; 复制代码 在上面的例子中,我们先定义了一个字符串变量v_string,然后...
lengthb(string)计算string所占的字节长度:返回字符串的长度,单位是字节 length(string)计算string所占的字符长度:返回字符串的长度,单位是字符 对于单字节字符,lengthb()和length()是一样的 可以用lengthb('string')=length('string') 判断字符串是否含有中文 select length('::') from dual; --结果是 2字符 ...
这个页面有XCode实现，核心查询部分共100多行代码，包括一个查询、一个总记录数分页、两个统计（就是业...
l length(char):返回字符串的长度。 l substr(char,m,n):取字符串的子串,m表示起点,n 代表取 n 个字符的意思 l replace(char1,search_string,replace_string) 替换 l instr(char1,char2,[,n[,m]]) 取子串在字符串的位置(特别取某一个特殊字符在原字符串中的位置) ...
select'Japan'nation,'Tokyo'city from dual)select nation,listagg(city,',')withinGROUP(order by city)asCities from temp group by nation 运行结果: 这是最基础的用法: LISTAGG(XXX,XXX) WITHIN GROUP( ORDER BY XXX), 用法就像聚合函数一样,通过Group by语句,把每个Group的一个字段,拼接起来,非常方便。
SELECT'Oracle LENGTH'string,LENGTH('Oracle LENGTH')LenFROMdual;Code language:SQL (Structured Query Language)(sql) See the followingemployeestable in thesample database: The following statement sorts the employees by the lengths of their first names. It uses theLENGTH()function in theORDER BYclause...
ResultSet rset = stmt.executeQuery ("select ROWID from EMP"); ... rset.close (); // or stmt.close (); rset.getString (1); ResultSets를 종료해야 하는 이유는 무엇입니까? 원래 JDBC 사양에서는 더 이상 접속할 수 없을 때 Conn...