未找到具有兼容参数的名为"JSON_ARRAYAGG“类型的”函数“的授权例程

Question

在使用JSON_ARRAYAGG函数时，没有发现具有兼容参数的名为"JSON_ARRAYAGG“类型的”函数“的授权例程出现错误：

    QUERY:
        SELECT JSON_OBJECT('ACCT_ID' VALUE acct_id, 
        'use_case list' VALUE 
        JSON_ARRAYAGG(
        JSON_OBJECT('use_case' VALUE use_case,
        'stage' VALUE stage))) 
        FROM NULLID.ProductRecommendations 
        GROUP BY acct_id;
            
    Error:
            FAILED  [SELECT - 0 rows, 0.009 secs]  1) [Code: -440, SQL State: 42884]  No authorized routine named "JSON_ARRAYAGG" of type "FUNCTION" having compatible arguments was found.. SQLCODE=-440, SQLSTATE=42884, DRIVER=4.26.14
                2) [Code: -727, SQL State: 56098]  An error occurred during implicit system action type "2". Information returned for the error includes SQLCODE "-440", SQLSTATE "42884" and message tokens "JSON_ARRAYAGG|FUNCTION".. SQLCODE=-727, SQLSTATE=56098, DRIVER=4.26.14  

我在示例表上尝试了这个查询，但仍然得到了相同的错误：

    Person Table:
    create table NULLID.person
    (
      id INT GENERATED BY DEFAULT AS IDENTITY NOT NULL,
      name        varchar(50),
      PRIMARY KEY (id)
    );
        
    Contacts Table:
        create table NULLID.contacts
        (
          id INT,
          person_id int,
          key   varchar(50),
          value varchar(100),
          foreign key (person_id) references person (id)
        );
        
    Insert Queries:
    insert into NULLID.person values (1, 'A');
    insert into NULLID.person values (2, 'B');
    insert into NULLID.contacts values (1, 1, 'EMAIL', 'a@b.com');
    insert into NULLID.contacts values (2, 1, 'PHONE', '123');
    insert into NULLID.contacts values (3, 2, 'EMAIL', 'b@b.com');
    insert into NULLID.contacts values (4, 2, 'PHONE', '456');
        
    Query:  
SELECT
    person_id,
    JSON_ARRAYAGG(key)
FROM
    contacts
GROUP BY person_id
        
        
    Error:
16:17:44  FAILED  [SELECT - 0 rows, 0.009 secs]  1) [Code: -440, SQL State: 42884]  No authorized routine named "JSON_ARRAYAGG" of type "FUNCTION" having compatible arguments was found.. SQLCODE=-440, SQLSTATE=42884, DRIVER=4.26.14
2) [Code: -727, SQL State: 56098]  An error occurred during implicit system action type "2". Information returned for the error includes SQLCODE "-440", SQLSTATE "42884" and message tokens "JSON_ARRAYAGG|FUNCTION".. SQLCODE=-727, SQLSTATE=56098, DRIVER=4.26.14  

Answer 1

请理解您必须使用正确的文档来匹配Db2产品平台。对于Db2，有三个主要平台(Linux/Unix/Windows(LUW)、Z/OS和I系列(as/400)。此外，DB2 on-云中的特性(以及一个不同的知识中心)与常规的Db2-LUW略有不同。

您引用了DB2in-i的一个页面(as/400)，它是一个不同的产品(具有不同的语法)，而不是云上的DB2。因此，Db2 on-cloud没有该函数json_arrayagg (尽管当前版本的Db2 for I系列确实具有该功能)。

请使用此处的db2 on-cloud正确的知识中心。

https://www.ibm.com/support/knowledgecenter/SSFMBX/com.ibm.swg.im.dashdb.kc.doc/welcome.html

对于云上的Db2，语法是使用函数、JSON_ARRAY和相关函数。您可以使用此查询查看哪些JSON函数可用：select routinename from syscat.routines where routinename like 'JSON%' (假设您有正确的访问权限)。