-- 创建存储过程CREATEPROCEDUREcount_char_occurrences(INinput_stringVARCHAR(255),INtarget_charCHAR(1))BEGINDECLAREcountINT;SETcount=0;DECLAREiINTDEFAULT1;WHILEi<=LENGTH(input_string)DOIFSUBSTRING(input_string,i,1)=target_charTHENSETcount=count+1;ENDIF;SETi=i+1;ENDWHILE;SELECTcount;END 1. 2. ...
SUBSTRING_INDEX(str,delim,count) Returns the substring from string str before count occurrences of the delimiter delim. If count is positive, everything to the left of the final delimiter (counting from the left) is returned. If count is negative, everything to the right of the final delimit...
binary etc. The data which is going to be stored in a column decides the datatype of the column. For example, if the column is going to store numerals, integer datatype can be used or if the column name is going to store a string of variable length, varchar can be used. For...
we will refer to these positions very frequently. Now, let us say we want to extract just “Sample” from the entire string. In our case, we would want it from position 11 to get it extracted. So, the function will look like something: ...
这应该可以达到目的：
If len is less than 1,the result is the empty string. 1.2SUBSTRING_INDEX Returns the substring from string strbefore count occurrences of the delimiter delim. If count is positive, everything to the left of thefinal delimiter (counting from the left) is returned. If count ...
commentonfunctionreplace(text,text,text)is'replace all occurrences in string of old_substr with new_substr'; AI代码助手复制代码 3、SQL将查询结果赋值 --查询表数据,给test_content字段并赋值selecttest_id,test_code,'测试数据'test_contentfrommy_test;--查询表数据给自定义 ABCD字段 并赋值selecttest_id...
官方文档:String Functions 注意: 字符串的下标从1开始; 如果函数要求的是整数参数,那么传入的非整数参数将会被自动转为最接近的整数。 1.ASCII ASCII(str) 返回字符串str的最左面字符的ASCII代码值。如果str是空字符串,返回0;如果str是NULL,返回NULL。
MIDExtracts a substring from a string (starting at any position) POSITIONReturns the position of the first occurrence of a substring in a string REPEATRepeats a string as many times as specified REPLACEReplaces all occurrences of a substring within a string, with a new substring ...
QUOTE() Escape the argument for use in an SQL statement REGEXP Pattern matching using regular expressions REPEAT() Repeat a string the specified number of times REPLACE() Replace occurrences of a specified string REVERSE() Reverse the characters in a string RIGHT() Return the specified rightmost...