![]() It increases the complexity of any code you write to do it, and the developer who needs to take over maintenance of your code after you have moved on to another project will curse your name. Storing data in a JSON document when you eventually want to use SQL expressions to search or update individual fields within the JSON document is a costly mistake. Now compare how difficult that is to: UPDATE content SET status = 1 WHERE name = 'Jack' ![]() Using this in an UPDATE looks like this: mysql> update example set content = json_set(content, concat(json_unquote(json_search(json_extract(content, '$.name'), 'one', 'Jack')), '.status'), '1') Now use it in a JSON_SET() call: mysql> select json_pretty(Ĭoncat(json_unquote(json_search(json_extract(content, '$.name'), 'one', 'Jack')), '.status'), status and you can get the full path to the field you want to update: mysql> select concat(json_unquote(json_search(json_extract(content, '$.name'), 'one', 'Jack')), '.status') as path from example Then you can search that array to get the array position: mysql> select json_search(json_extract(content, '$.name'), 'one', 'Jack') as root from example Here's a trick: You can extract the name field, and that turns into an array of those values: mysql> select json_extract(content, '$.name') as a from example A maximum of 3 JSON columns per NDB table is supported. 1 UPDATE t SET jsoncol JSONSET (jsoncol, '.name', 'Knut') WHERE id 123 This update can be performed as a partial update because it takes a JSON column ( jsoncol ), modifies one of its members, and then stores it into the same column as it reads from ( jsoncol ). mysql> select j.* from example cross join json_table(content, '$' columns( MySQL NDB Cluster 8.0 supports JSON columns and MySQL JSON functions, including creation of an index on a column generated from a JSON column as a workaround for being unable to index a JSON column. And that doesn't tell you the path to the element, it only allows you to return a specific row out of the array. To search for a key/value pair, you need to use JSON_TABLE() and that requires you upgrade to MySQL 8.0. mysql> select json_unquote(json_search(content, 'one', 'Jack')) as path from example If "Jack" occurs in some other field, that would also be found. The JSON values stored in that column, are just a way to differenciate a row from another, nothing more. But later, I was thinking about using index to speed up the queries, and because of that, change the JSON type to maybe a TEXT type to create a index with the 4 columns. ![]() You can get the path to a JSON element with JSON_SEARCH(), but you can only search by value, not by a key/value pair. From the beginning I'm using the filter column as a JSON type of MySQL. The solution in that case depends on you knowing which array element your pseudo-record exists in. The question like yours has come up before on Stack Overflow, for example JSON update single value in MySQL table. ![]() mysql> select json_pretty(json_replace(content, '$.status', '1')) as j Although JSON data should preferably be stored in a NoSQL database such as MongoDB, you may still encounter tables with JSON data from time to time. The SET clause indicates which columns to modify and the values they should be given. Towards Data Science 6 min read - 1 MySQL supports a native JSON data type that supports automatic validation and optimized storage and access of the JSON documents. So in this case, we can see that the array element is $ but if you didn't know that, you couldn't use this solution. Multiple-table syntax: UPDATE LOWPRIORITY IGNORE tablereferences SET assignmentlist WHERE wherecondition For the single-table syntax, the UPDATE statement updates columns of existing rows in the named table with new values. You can use JSON_REPLACE() or JSON_SET(), but both require that you know the path to the field you want to change. If the parameter path is not a valid path expression or contains * or **, MySQL will give an error.This is very awkward, nearly impossible with MySQL's JSON functions.You can use JSON_VALID() to verify the JSON document. MySQL will give an error if the parameter json is not a valid JSON document.There will happen an error in the following cases: This function will return NULL if the JSON document or path is NULL. To ensure the inserted data’s data type is correct, please convert value as a JSON type value. If value is a string, the JSON_REPLACE() function writes it to the JSON document as a JSON string. If the specified path exists in the JSON document, update the value matching the path if not, insert data at the corresponding path. You can provide multiple pairs of path-value parameters to set multiple data at once. The JSON_SET() function inserts or updates data in a JSON document and returns a new JSON document. A valid path expression that cannot contain * or **.
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