MySQL query gadget (I) replace a property value of the object in the JSON array in the JSON format string field

Catalog

JSON_SEARCH function

Implementation steps

1. First step ： lookup WORKFLOW_APPROVAL The index number in the array

2. The second step ： Replace double quotes

3. The third step ： Replace with router attribute

4. Step four ： Use JSON_REPLACE Conversion of function to UPDATE Statement to update

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Recently, I encountered a problem in my project , stay mysql There is a... In the database table json Format string type field , There is a collection of objects , I want to put id=6 In the record of value The object attribute of the object array in the value name The value of is WORKFLOW_APPROVAL Of router Property values are set by A Change to B.

It sounds a little convoluted , Is to update a string json A property value of an object element in the format string .

JSON_SEARCH function

The solution to this problem depends on JSON_SEARCH function . Let's take a look at the usage of this function .

JSON_SEARCH(json_doc,one_or_all,search_str [,escape_char [,path] ...])

adopt JSON_SEARCH function , Returns the matching key Corresponding JSON An array of paths , If it does not exist , Then return to NULL

Use the following conditions to return NULL

• if  json_doc ,search_str, or path Any one of the parameters is NULL, Then return to NULL

• Does not exist in the document path

• search_str Not found

In the following cases, an error will be reported

• json_doc For illegal JSON file

• path Is an illegal path expression

• one_or_all  The parameter is not  one  or  all

Argument parsing ：

• json_doc： To query Json  file , For example, in my demand value Field

• one_or_all： End condition of query

  • one： The search terminates after the first occurrence , And returns a path string . If not defined, which match should be considered first .

  • all： Search returns all matching path strings , Therefore, duplicate paths are not included . If there are multiple strings , They are automatically wrapped as an array . The order of array elements is uncertain .

• search_str： Parameter value to search , For example, in my demand WORKFLOW_APPROVAL
  • escape_char： Specify escape character .escape_char  Parameter must be constant when specified （ Empty or one character ）, When escape_char Parameter is NULL Or if it doesn't exist , System default use  \  As escape character .
  • path The specified scope is always the document to search for or operate on , With leading $ Character representation . The path branch consists of the period character  . Separate . The cells in the array are represented by [N] Express , The format is the same as that of normal access to array elements , for example  $.x  representative JSON In the document x Corresponding value ,$[1].y representative JSON The second data element in the document y The corresponding value .

  For specific usage, please refer to Examples of official documents

notes ： stay search_str in , wildcard % and _ Can be like in LIKE It works the same way on the Internet , among % Used to match multiple characters （ Include 0）, _ Only one character can be matched .

Implementation steps

1. First step ： lookup WORKFLOW_APPROVAL The index number in the array

First of all, find json Array name yes WORKFLOW_APPROVAL The index number of .

select JSON_SEARCH(
               value,
               'one',
               'WORKFLOW_APPROVAL',
               null,
               '$**.name')
from hx_maintain_param
where id = 6

2. The second step ： Replace double quotes

As a result of the query path The expression is quoted , If the quoted expression is directly executed, an error will be reported , Therefore use REPLACE Function remove the double quotation marks .

select REPLACE(
               JSON_SEARCH(
                       value,
                       'one',
                       'WORKFLOW_APPROVAL',
                       null,
                       '$**.name'),
                '"',
                ''
           )
from hx_maintain_param
where id = 6

3. The third step ： Replace with router attribute

If you will $[35].name  This expression goes to JSON_REPLACE Function , It means that name The value of the property , But I want to replace yes router The value of the property , Therefore, you also need to use REPLACE Function name Replace with router.

select
       REPLACE(
               REPLACE(
                       JSON_SEARCH(
                               value,
                               'one',
                               'WORKFLOW_APPROVAL',
                               null,
                               '$**.name'),
                       '"',
                       ''
                   ),
                'name',
                'router'
           )
from hx_maintain_param
where id = 6

4. Step four ： Use JSON_REPLACE Conversion of function to UPDATE Statement to update

The final statement ：

UPDATE hx_maintain_param
SET value =
        JSON_REPLACE(
                value,
                REPLACE(
                        REPLACE(
                                JSON_SEARCH(
                                        value,
                                        'one',
                                        'WORKFLOW_APPROVAL_PASS',
                                        null,
                                        '$**.name'),
                                '"',
                                ''
                            ),
                        'name',
                        'router'
                    ),
                '/manageAudit/manageAuditMyList/detail?auditId=:auditId&title=:title&state=:state&auditState=:auditState&category=:category&secondCategory=:secondCategory'
            )
where id = 6;

I am a Seven, A tireless program , I hope this article can be beneficial to you

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