Mysql5.6 parsing JSON strings (supporting complex nested formats)

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mysql5.6 analysis JSON character string

Support complex nested formats

mysql5.6 And the following analysis json Method

Let's talk about the background of the problem first

Here is the corresponding code  

mysql5.6 analysis JSON character string Support complex nested formats

I don't say much nonsense , On the first code .

CREATE FUNCTION `json_parse`(`jsondata` longtext,`keyname` text) RETURNS text CHARSET utf8BEGINDECLARE delim VARCHAR(128);DECLAREresult longtext;DECLARE startpos INTEGER;DECLARE endpos INTEGER;DECLARE endpos1 INTEGER; DECLARE findpos INTEGER;DECLARE leftbrace INTEGER;DECLARE tmp longtext; DECLARE tmp2 longtext;DECLARE Flag INTEGER;SET delim = CONCAT('"', keyname, '": "');SET startpos = locate(delim,jsondata);IF startpos > 0 THENSET findpos = startpos+length(delim);SET leftbrace = 1;SET endpos = 0;SET Flag =1;get_token_loop: repeat IF substr(jsondata,findpos,2)='\\"' THENSET findpos = findpos + 2;iterate get_token_loop;ELSEIF substr(jsondata,findpos,2)='\\\\' THENSET findpos = findpos + 2;iterate get_token_loop;ELSEIF substr(jsondata,findpos,1)='"' AND Flag = 1 THEN SET endpos = findpos;SET findpos = LENGTH(jsondata)+1;leave get_token_loop;END IF;SET findpos = findpos + 1;UNTIL findpos > LENGTH(jsondata) END repeat;IF endpos > 0 THENSELECT substr(jsondata,startpos+length(delim)# Take out value The starting position of the value ,endpos# Take out value The end position of the value -(startpos+length(delim))# subtract value The starting position of the value , obtain value Value character length ) INTO resultFROM DUAL;SET result= replace(result,'\\"','"');SET result= replace(result,'\\\\','\\');ELSE SET result=null;END IF;/*SELECT substr(jsondata,locate(delim,jsondata)+length(delim)# Take out value The starting position of the value ,locate('"',jsondata,locate(delim,jsondata)+length(delim))# Take out value The end position of the value -(locate(delim,jsondata)+length(delim))# subtract value The starting position of the value , obtain value Value character length ) INTO resultFROM DUAL;*/ELSESET delim = CONCAT('"', keyname, '": {');SET startpos = locate(delim,jsondata);IF startpos > 0 THENSET findpos = startpos+length(delim);SET leftbrace = 0;SET endpos = 0;SET Flag =0;get_token_loop: repeat IF substr(jsondata,findpos,2)='{"' THENSET leftbrace = leftbrace + 1;SET findpos = findpos + 2;iterate get_token_loop;ELSEIF substr(jsondata,findpos,2)='\\"' THENSET findpos = findpos + 2;iterate get_token_loop;ELSEIF substr(jsondata,findpos,3)=': "' THENSET Flag = 1;SET findpos = findpos + 3;iterate get_token_loop;ELSEIF substr(jsondata,findpos,1)='"' THENSET Flag = 0;ELSEIF substr(jsondata,findpos,1)='}' AND Flag = 0 THENIF leftbrace > 0 THENSET leftbrace = leftbrace - 1;ELSE SET endpos = findpos;SET findpos = LENGTH(jsondata)+1;END IF;END IF;SET findpos = findpos + 1;UNTIL findpos > LENGTH(jsondata) END repeat;IF endpos > 0 THENSELECT substr(jsondata,startpos+length(delim)# Take out value The starting position of the value ,endpos# Take out value The end position of the value -(startpos+length(delim))# subtract value The starting position of the value , obtain value Value character length ) INTO resultFROM DUAL;SET result=CONCAT("{",result, '}');ELSE SET result=null;END IF;ELSE SET delim = CONCAT('"', keyname, '": [');SET startpos = locate(delim,jsondata);IF startpos > 0 THENSET findpos = startpos+length(delim);SET leftbrace = 0;SET endpos = 0;SET tmp = substring_index(jsondata,delim,-1);SET tmp2 = substring_index(tmp,']',1); IF locate('[',tmp2) =0 THENSET endpos = locate(']',tmp);SET endpos = endpos+findpos-1; ELSEget_token_loop: repeat IF substr(jsondata,findpos,2)='\\"' THENSET findpos = findpos + 2;iterate get_token_loop;ELSEIF substr(jsondata,findpos,3)=': "' THENSET Flag = 1;SET findpos = findpos + 3;iterate get_token_loop;ELSEIF substr(jsondata,findpos,1)='[' AND Flag = 0 THENSET leftbrace = leftbrace + 1;SET findpos = findpos + 1;iterate get_token_loop;ELSEIF substr(jsondata,findpos,1)='"' THENSET Flag = 0;ELSEIF substr(jsondata,findpos,1)=']' AND Flag = 0 THENIF leftbrace > 0 THENSET leftbrace = leftbrace - 1;ELSE SET endpos = findpos;SET findpos = LENGTH(jsondata)+1;END IF;END IF;SET findpos = findpos + 1;UNTIL findpos > LENGTH(jsondata) END repeat;END IF;IF endpos > 0 THENSELECT substr(jsondata,startpos+length(delim)# Take out value The starting position of the value ,endpos# Take out value The end position of the value -(locate(delim,jsondata)+length(delim))# subtract value The starting position of the value , obtain value Value character length ) INTO resultFROM DUAL;SET result=CONCAT("[",result, ']');ELSE SET result=null;END IF;ELSE SET delim = CONCAT('"', keyname, '": ');SET startpos = locate(delim,jsondata);IF startpos > 0 THENSET endpos = locate(',',jsondata,startpos+length(delim));SET endpos1 = locate('}',jsondata,startpos+length(delim));IF endpos>0 OR endpos1>0 THENIF endpos1>0 AND endpos1 < endpos OR endpos =0 THENSET endpos = endpos1;END IF;SELECT substr(jsondata,startpos+length(delim)# Take out value The starting position of the value ,endpos# Take out value The end position of the value -(locate(delim,jsondata)+length(delim))# subtract value The starting position of the value , obtain value Value character length ) INTO resultFROM DUAL;IF STRCMP(result,'null')=0 THENSET result=null;END IF;ELSE SET result=null;END IF;ELSE SET result=null;END IF;END IF;END IF;END IF;if result='' and RIGHT(keyname,2)='Id' thenSET result=null;end if;RETURN result;END

jsondata It needs to be strict json Format （ Notice the space between commas and semicolons and double quotes ）

SET jsondata='{"CurrentPage": 1, "data": [{"config": "123"}, {"config": "456"}], "PageSize": 10}' SELECT json_parse(jsondata, 'CurrentPage') INTO CurrentPage;SELECT json_parse(jsondata, 'data') INTO data;

If you want to get config The content of , You can do this

        SET count = (LENGTH(data)-LENGTH(REPLACE(data,'},','')))/2+1;        SET i = 0;        WHILE i < count DO            SET SetObject = SUBSTRING_INDEX(SUBSTRING_INDEX(data,'},',i+1),'},',-1);            IF LENGTH(SetObject)>0 THEN                SELECT json_parse(SetObject, 'config') INTO config;                END IF;            SET i = i + 1;        END WHILE;

deficiencies ,jsondata When there is a lot of data , There will be efficiency problems .

mysql5.6 And the following analysis json Method

Previously, I found that the online query platform in the company is MySQL5.6, Out-of-service JSON_EXTRACT, Nor can you use stored procedures , So I can only compile a simple query by myself , A few pieces of data can still be checked , If there's a lot of data , It is estimated that more resources will be consumed .

Let's talk about the background of the problem first

I want to '{"platform":"Android","source":"tt","details":null}' Found in this string of things source This key Corresponding value value .

This method is to find source":" The starting position and length of this string , In this way, we can find value The starting position of the value ; The first one after finding this string " Position of appearance , You can get value The end position of the value .

recycling substr function , You can take out the corresponding position .

Here is the corresponding code  SELECT '{"platform":"Android","source":"tt","details":null}' as 'sample',substr( '{"platform":"Android","source":"tt","details":null}' ,locate('source":"','{"platform":"Android","source":"tt","details":null}') +length('source":"')# Take out value The starting position of the value ,locate( '"' ,'{"platform":"Android","source":"tt","details":null}' ,locate('source":"','{"platform":"Android","source":"tt","details":null}') +length('source":"') )# Take out value The end position of the value -( locate('source":"','{"platform":"Android","source":"tt","details":null}') +length('source":"') )# subtract value The starting position of the value , obtain value Value character length ) as resultFROM DUAL

After running , You get result Result , Namely tt. If you need other elements , Just replace the corresponding key Values and fields , Just fine .

The above is personal experience , I hope I can give you a reference , I also hope you can support the software development network .