一、解析json数组 selectjson_array_elements(lv_num_json)->'l1' lv,json_array_elements(lv_num_json)->'num' numfrom( select '[{"l1":8,"num":1}, {"l1":9,"num":10}]'::json lv_num_json )ast1 查询结果 二、解析json对象 SELECTjson_object_field('{"l1":8,"num":1}','l1')asl...
例如,我使用以下函数将rows转换为PostgreSQL 9.2中的json select row_to_json(row(productid, product)) from gtab04; 这将返回低于结果的结果 row_to_json --- {"f1":3029,"f2":"DIBIZIDE M TAB"} {"f1":3026,"f2":"MELMET 1000 SR TAB"} {"f1":2715,"f2":"GLUCORE 浏览0提问于2014-08-29...
bank=# select to_json(t) from (select code,title from films) t; {"code":"UA502","title":"Bananas"} {"code":"UA123","title":"Apples"} {"code":"CN111","title":"Onec More"} json_array_length(json) bank=# select json_array_length(array_to_json(array_agg(t),true)) from (...
results <- query_ conn "SELECT json_column FROM table_name" 处理查询结果。由于postgresql-simple是一个类型安全的库,它需要定义一个数据类型来表示查询结果的结构。在这个例子中,假设查询结果是一个包含JSON值的列表。 代码语言:txt 复制 data MyData = MyData { jsonData :: Value } instance Fro...
column "myapp_mymodel.jsonfield" must appear in the GROUP BY clause or be used in an aggregate function The SQL query seems OK at first glance: SELECT (("mymodel"."jsonfield" -> 'subfield'))::text, COUNT("mymodel"."id") AS "id_count" FROM "mymodel" GROUP BY (("mymodel"."...
select extract(day from now()); //取当前日 2. 字符串操作 select 'aaaaa'||'bbbbbb' as f1; //字符串相加 select char_length('abcdefgh'); //字符串长度 select position('fgh' in 'abcdefgh'); //查找子串 select substring ( 'abcdefgh' from 5 for 3); //取一段字符串 select lower(...
import com.alibaba.fastjson.annotation.JSONField; import com.alibaba.fastjson.serializer.ToStringSerializer; import lombok.Data; /** *@author lv.gui *@date 创建时间:2021年9月21日 下午11:01:54 *@description */ @Data @Entity @Table(name = "user") ...
> select * from users order by random();随机排序 > select * from users order by random() limit 1; 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 更新和删除 * update [table] set [field=newvalue,...] where ... ...
grant SELECT ON pg_stat_database to datakit; 操作步骤 指标采集 以下主要是通过主机的方式进行采集,进入 DataKit 安装目录下的 conf.d/db 目录,复制 postgresql.conf.sample 并命名为 postgresql.conf。 注意:address 定义了连接到 postgresql 服务器的 URI,这里的 datakit 是用户名,PASSWORD 应被替换为实际的密...
The trade-off is a small additional cost on writing to the jsonb field. JSONField uses jsonb. As a result, this field requires PostgreSQL ≥ 9.4 and Psycopg2 ≥ 2.5.4. Querying JSONField¶ We will use the following example model: from django.contrib.postgres.fields import JSONField from...