Plsql—如何从函数返回json并将其使用到另一个变量或打印为json结构

我想用返回json结构的函数创建一个包，这是包中的代码：

包装规格

包体

我测试了这段代码，并在json结构被注释后打印出来**

现在，我想从另一个plsql中使用此函数，并希望使用以下代码查看结果：

案例1

但我看不到我想要的结果。我看到这个错误：

错误->案例1：

案例2

第1步：

第2步：

错误->案例2：

独立运行

函数编译正确，没有错误 但当我想使用它时：

DECLARE
    SALIDA CLOB;
BEGIN
    SALIDA := otro_get_json(174, 'my_table_name');
    DBMS_OUTPUT.put_line(SALIDA);

END;
/

错误->功能独立：

出了什么问题，我该如何解决

我的函数返回如下内容：

{
  "my_table_name": [
    {
      "created": "2020-06-04T08:10:09.000000000Z",
      "created_by": "APEX_APP",
      "updated": "2020-06-04T10:10:09.295632000Z",
      "updated_by": "APEX_APP",
      "id": 174,
      "text": "ALL",
      "part": 2770,
      "code": 2212,
      "date": "2017-01-01T00:00:00.000000000Z",
      "percentage": -4.98
    }
  ]
}

但我需要查看或打印SALIDA变量

---

非常感谢

为了复制您的错误，我将varchar2的大小减少到100，用于v_stmt

     create or replace function get_emp(p_no in number,p_table_name in varchar2) return clob is 
        --declare
            v_stmt VARCHAR2(100);
            l_sep varchar2(1) := chr(10);
            l_tab varchar2(1) := chr(9);
            up_column VARCHAR2(50);
            low_column VARCHAR2(50);
            cur_asc SYS_REFCURSOR;
            Vcdogcur SYS_REFCURSOR;
            id_ccd number:=p_no;
            --id_ccd number:= 7369;
            first boolean := true;
            -- json_clob clob;
        begin

            v_stmt := 'select *';

            open cur_asc for 
                SELECT column_name as up_column
                      ,lower(column_name) as low_column
                FROM USER_TAB_COLUMNS
                WHERE table_name = upper('p_table_name');
            loop 
                FETCH cur_asc
                INTO  up_column, low_column;
                EXIT WHEN cur_asc%NOTFOUND;
                if not first then
                    v_stmt := v_stmt || ',';
                end if;
                first := false;
                v_stmt := v_stmt || l_sep || l_tab ||up_column || ' as ' || low_column;
            END LOOP;
            --v_stmt := v_stmt || l_sep || 'from my_table' || l_sep ||'where id = ' || id_ccd || ';';
            v_stmt := v_stmt || l_sep || 'from '||p_table_name|| l_sep ||'where empno = ' || id_ccd;


            --v_stmt := v_stmt || l_sep || 'from my_table' || l_sep ||'where id = ' || id_ccd;
CLOSE cur_asc;             
DBMS_OUTPUT.PUT_LINE('salida: ' || v_stmt || 'length of v_stmt: ' || to_char(length(v_stmt)));

            open Vcdogcur for v_stmt;
                APEX_JSON.initialize_clob_output;
                APEX_JSON.open_object;
                APEX_JSON.write(p_table_name, Vcdogcur);
                APEX_JSON.close_object;
              --  DBMS_OUTPUT.put_line(APEX_JSON.get_clob_output);

              return APEX_JSON.get_clob_output;
               APEX_JSON.free_output;  

        end;


SQL> select get_emp(7369,'emp') from dual;
ERROR:
ORA-06502: PL/SQL: numeric or value error: character string buffer too small
ORA-06512: at "SCOTT.GET_EMP", line 34



no rows selected

现在在增加varchar2大小之后

SQL> select get_emp(7369,'emp') from dual;

GET_EMP(7369,'EMP')
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
{
"emp":[
{
"EMPNO":7369
,"ENAME":"SMITH"
,"JOB":"CLERK"
,"MGR":7902
,"HIREDATE":"1980-12-17T00:00:00Z"
,"SAL":800
,"DEPTNO":20
}
]
}

---

注意：-在关闭当前asc后添加长度；如果您好奇的话，可以找出v_stmt的长度。

您的匿名pl/sql块没有问题，但是某个变量导致了错误，不确定它是否与您的函数相关。检查行ORA-06512:en MIBDES.HOMESERVER_UTILS，línea 48是否创建了包规范？@Sam，我期待另一种答案，我也收到了这个消息，但我不知道该怎么办。@Kumar，是的，我更新了我的问题，但是用同样的错误尝试创建没有包体的独立函数并执行它，看看它是否有效。在我的情况下，为了使它有效，我将最大大小设置为varchar2->varchar232767，现在它可以工作了。谢谢@Kumar

create table temp_json (
  json_data blob not null
);
alter table temp_json
  add constraint temp_data_json 
  check ( json_data is json );

DECLARE
    SALIDA CLOB;
BEGIN

    insert into temp_json (JSON_DATA) values (mibdes.homeserver_utils.get_json(174, 'my_table_name'));

END;
/

Informe de error -
ORA-06502: PL/SQL: error : buffer de cadenas de caracteres demasiado pequeño numérico o de valor
ORA-06512: en "my_schema.my_utils", línea 48
ORA-06512: en línea 14
06502. 00000 -  "PL/SQL: numeric or value error%s"
*Cause:    An arithmetic, numeric, string, conversion, or constraint error
           occurred. For example, this error occurs if an attempt is made to
           assign the value NULL to a variable declared NOT NULL, or if an
           attempt is made to assign an integer larger than 99 to a variable
           declared NUMBER(2).
*Action:   Change the data, how it is manipulated, or how it is declared so
           that values do not violate constraints.

CREATE OR REPLACE FUNCTION otro_get_json (id_row     IN NUMBER, 
                                     table_name IN VARCHAR2) RETURN CLOB 
IS 
  --json_clob CLOB; 
  v_stmt     VARCHAR2(1000); 
  l_sep      VARCHAR2(1) := Chr(10); 
  l_tab      VARCHAR2(1) := Chr(9); 
  up_column  VARCHAR2(50); 
  low_column VARCHAR2(50); 
  cur_asc    SYS_REFCURSOR; 
  vcdogcur   SYS_REFCURSOR; 
  --id_ccd     NUMBER; 
  first      BOOLEAN := TRUE; 
BEGIN 
    --id_ccd := id_row; 

    v_stmt := 'select '; 

    OPEN cur_asc FOR 
      SELECT column_name        AS up_column, 
             Lower(column_name) AS low_column 
      FROM   user_tab_columns 
      WHERE  table_name = Upper(table_name); 

    LOOP 
        FETCH cur_asc INTO up_column, low_column; 
        EXIT WHEN cur_asc%NOTFOUND; 
        IF NOT first THEN 
          v_stmt := v_stmt 
                    || ','; 
        END IF; 

        first := FALSE; 
        v_stmt := v_stmt 
                  || l_sep 
                  || l_tab 
                  ||up_column 
                  || ' as "' 
                  || low_column 
                  || '"'; 
    END LOOP; 

    v_stmt := v_stmt 
              || l_sep 
              || 'from ' 
              || table_name 
              || l_sep 
              ||'where id = ' 
              || id_row; 

    --dbms_output.Put_line(v_stmt); 
    CLOSE cur_asc; 
    OPEN vcdogcur FOR v_stmt; 
    apex_json.initialize_clob_output; 
    apex_json.open_object; 
    apex_json.WRITE(table_name, vcdogcur); 
    apex_json.close_object; 
    --dbms_output.Put_line(apex_json.get_clob_output); 

    --json_clob := APEX_JSON.get_clob_output; 
    --APEX_JSON.free_output; 
    --CLOSE Vcdogcur; 
    --return json_clob; 
    RETURN apex_json.get_clob_output; 
END; 
/

DECLARE
    SALIDA CLOB;
BEGIN
    SALIDA := otro_get_json(174, 'my_table_name');
    DBMS_OUTPUT.put_line(SALIDA);

END;
/

Informe de error -
ORA-06502: PL/SQL: error : buffer de cadenas de caracteres demasiado pequeño numérico o de valor
ORA-06512: en "my_schema.OTRO_GET_JSON", línea 34
ORA-06512: en línea 10
06502. 00000 -  "PL/SQL: numeric or value error%s"
*Cause:    An arithmetic, numeric, string, conversion, or constraint error
           occurred. For example, this error occurs if an attempt is made to
           assign the value NULL to a variable declared NOT NULL, or if an
           attempt is made to assign an integer larger than 99 to a variable
           declared NUMBER(2).
*Action:   Change the data, how it is manipulated, or how it is declared so
           that values do not violate constraints.

{
  "my_table_name": [
    {
      "created": "2020-06-04T08:10:09.000000000Z",
      "created_by": "APEX_APP",
      "updated": "2020-06-04T10:10:09.295632000Z",
      "updated_by": "APEX_APP",
      "id": 174,
      "text": "ALL",
      "part": 2770,
      "code": 2212,
      "date": "2017-01-01T00:00:00.000000000Z",
      "percentage": -4.98
    }
  ]
}

     create or replace function get_emp(p_no in number,p_table_name in varchar2) return clob is 
        --declare
            v_stmt VARCHAR2(100);
            l_sep varchar2(1) := chr(10);
            l_tab varchar2(1) := chr(9);
            up_column VARCHAR2(50);
            low_column VARCHAR2(50);
            cur_asc SYS_REFCURSOR;
            Vcdogcur SYS_REFCURSOR;
            id_ccd number:=p_no;
            --id_ccd number:= 7369;
            first boolean := true;
            -- json_clob clob;
        begin

            v_stmt := 'select *';

            open cur_asc for 
                SELECT column_name as up_column
                      ,lower(column_name) as low_column
                FROM USER_TAB_COLUMNS
                WHERE table_name = upper('p_table_name');
            loop 
                FETCH cur_asc
                INTO  up_column, low_column;
                EXIT WHEN cur_asc%NOTFOUND;
                if not first then
                    v_stmt := v_stmt || ',';
                end if;
                first := false;
                v_stmt := v_stmt || l_sep || l_tab ||up_column || ' as ' || low_column;
            END LOOP;
            --v_stmt := v_stmt || l_sep || 'from my_table' || l_sep ||'where id = ' || id_ccd || ';';
            v_stmt := v_stmt || l_sep || 'from '||p_table_name|| l_sep ||'where empno = ' || id_ccd;


            --v_stmt := v_stmt || l_sep || 'from my_table' || l_sep ||'where id = ' || id_ccd;
CLOSE cur_asc;             
DBMS_OUTPUT.PUT_LINE('salida: ' || v_stmt || 'length of v_stmt: ' || to_char(length(v_stmt)));

            open Vcdogcur for v_stmt;
                APEX_JSON.initialize_clob_output;
                APEX_JSON.open_object;
                APEX_JSON.write(p_table_name, Vcdogcur);
                APEX_JSON.close_object;
              --  DBMS_OUTPUT.put_line(APEX_JSON.get_clob_output);

              return APEX_JSON.get_clob_output;
               APEX_JSON.free_output;  

        end;


SQL> select get_emp(7369,'emp') from dual;
ERROR:
ORA-06502: PL/SQL: numeric or value error: character string buffer too small
ORA-06512: at "SCOTT.GET_EMP", line 34



no rows selected

SQL> select get_emp(7369,'emp') from dual;

GET_EMP(7369,'EMP')
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
{
"emp":[
{
"EMPNO":7369
,"ENAME":"SMITH"
,"JOB":"CLERK"
,"MGR":7902
,"HIREDATE":"1980-12-17T00:00:00Z"
,"SAL":800
,"DEPTNO":20
}
]
}