```sql json_extract_scalar(json_document, path) ``` - `json_document`是包含JSON数据的列或表达式。 - `path`是JSON路径,用于指定要提取的值的位置。 以下是一个简单的示例: 假设有一个表`my_table`,其中包含一个名为`json_data`的JSON列: ```sql CREATE TABLE my_table ( id INT, json_data ...
首先,使用JSON函数是在执行SQL的时候,实时的对JSON数据进行解析,其性能受数据量大小和json结构复杂度的影响。 因此如果数据量很大或者结构复杂,并且对查询性能有要求,同时json对象的结构相对比较固定,建议优先考虑对JSON叶子节点单独建立字段索引的方式。 而如果数据量比较小,或者出于成本考虑,则可以不建立json叶子节点索引...
用的还是Hbase的TableInputFormat相关的API。 基础软件版本如下： 直接上代码如下： 上面的少量代码，已经...
ENmysql中json函数： 方法函数描述补充 创建jsonjson_array创建json数组 json_object创建json对象...
https://stackoverflow.com/questions/53038338/json-object-is-null-but-somehow-its-children-are-not I thought this might be an SQL problem, but it works as expected in Spark's SQL API (using get_json_object as a drop-in replacement of json_extract_scalar): select json_extract_scalar('{"...
then sql such as select json_extract_scalar(properties, '$.num_clicks', 'LONG', 0) from tab returns 5514400327644544000. That is because function parses as Double and then casts to long. This PR first tries to parse as Long and then reverts to double to support scientific notation. Repor...
在Spark SQL或Scala中使用JSON_EXTRACT或JSON_EXTRACT_SCALARThe from_json spark column method may help...
In this article, we will explore JSON_VALUE() function in SQL Server to extract scalar values from JSON data. Introduction to JSON JSON is an acronym for “JavaScript Object Notation”. It is a lightweight data exchange language. If you are familiar with XML, it is a bit hard to under...
如果异常类型是TApplicationException，并且异常原因是missing_result，那么可以返回null。否则，应该继续向上...
In this article, we will explore JSON_VALUE() function in SQL Server to extract scalar values from JSON data. Introduction to JSON JSON is an acronym for “JavaScript Object Notation”. It is a lightweight data exchange language. If you are familiar with XML, it is a bit hard to under...