sql：使用動態列和值更新動態表

Question

目標：我想創建一個可以更新表的函數，並且條件（在哪里）是動態的。如下：

create or replace function f_update(
    tablename          text,      --the table name updated
    update_fields      text,      --fields and values as json 
                                  --[{"fieldName":"id","fieldValue":1},
                                  --{"fieldName":"name","fieldValue":"admin"},
                                  --{"fieldName":"salary,"fieldValue":6000.00}]
    condition_fields   text,      --condition: json like above
    out return_value   text       --return value
) as $$
declare
    ex_sql             text;
    recs               record;
begin
    ex_sql:='update '||quote_ident(tablename)||' set ';
    --set values to the column
    for recs in select * from json_to_recordset(update_fields::json) as x( field_name text,field_value text) loop
        if json_typeof(recs.field_value) ='numeric' then 
            ex_sql:=ex_sql|| recs.field_name || '=' ||  recs.field_value ||',';
        else 
            ex_sql:=ex_sql|| recs.field_name || '='''|| recs.field_value || ''',';
        end if;
    end loop;
    ex_sql:= substring(ex_sql from 0 for length(ex_sql)-1);

    --setting conditions 
    ex_sql:=ex_sql||' where 1=1';
    for recs in select * from json_to_recordset(condition_fields::json) as x( field_name text,field_value text) loop
        if json_typeof(recs.field_value) ='numeric' then 
            ex_sql:=ex_sql|| ' and ' || recs.field_name || '=' ||  recs.field_value ||',';
        else 
            ex_sql:=ex_sql|| ' and ' || recs.field_name || '='''|| recs.field_value || ''',';
        end if;
    end loop;
    ex_sql:= substring(ex_sql from 0 for length(ex_sql)-1);
    return_value:=ex_sql;
end;
$$ language plpgsql;

-當然，它不能通過！ -問題：-如何為列設置值？ -因為表格是動態的，所以列的類型是未知的！

Answer 1

我改變了功能：

create or replace function f_update(
    tablename          text,          
    update_feilds      text,          
    condition_feilds   text,       
    out return_value   text        
) as $$
declare
    ex_sql             text;
    recs               record;
begin
    ex_sql:='update '||quote_ident(tablename)||' set ';
    for recs in select * from json_to_recordset(update_feilds::json) as x( feild_name text,feild_value text) loop
        if json_typeof(to_json(recs.feild_value)) ='number' then 
            ex_sql:=ex_sql|| recs.feild_name || '=' ||  recs.feild_value ||',';
        else 
            ex_sql:=ex_sql|| recs.feild_name || '='''|| recs.feild_value || ''',';
        end if;
    end loop;
    ex_sql:= substring(ex_sql from 0 for length(ex_sql));


    ex_sql:=ex_sql||' where 1=1';
    for recs in select * from json_to_recordset(condition_feilds::json) as x( feild_name text,feild_value text) loop
        if json_typeof(to_json(recs.feild_value)) ='number' then 
            ex_sql:=ex_sql|| ' and ' || recs.feild_name || '=' ||  recs.feild_value ||',';
        else 
            ex_sql:=ex_sql|| ' and ' || recs.feild_name || '='''|| recs.feild_value || ''',';
        end if;
    end loop;
    ex_sql:= substring(ex_sql from 0 for length(ex_sql));
    return_value:=ex_sql;
end;
$$ language plpgsql;

經過一些測試：我通過了參數：tableName：'test'update_feilds'[{“ field_name”：“ name”，“ field_value”：“ ssqhan”}，{“ field_name”：“ salary”，“ field_value”：5200.00 }]'condition_feilds'[{“ field_name”：“ id，” field_value“：1}]'

和我得到的SQL字符串為：更新測試集名稱=“ ssqhan”，工資=“ 5200.00”，其中1 = 1和ID =“ 1”

但是，這不是我的意思：id int名稱文本，salay號！ sql應該像：更新測試集名稱=“ ssqhan”，工資= 5200.00其中1 = 1和id = 1，這就是我想要的。

Answer 2

我得到了另一個這樣的代碼：

create or replace function f_update_all(
    tablename          text,      
    update_feilds      text,       
    condition_feilds   text,       
    out return_value   text        
) as $$
declare
    ex_sql             text;
    recs               record;
    _key               text ;
    _value             text;
begin
    ex_sql:='update '||quote_ident(tablename)||' set ';
    --setting values for updated table
    for recs in select * from json_array_elements(update_feilds::json)   loop
        _key   := recs.value ->> 'feild_name';
        _value := recs.value ->> 'feild_value' ;


        if json_typeof(recs.value -> 'feild_value') ='number' then 
            ex_sql:=ex_sql|| _key || '=' ||  _value ||',';
        else 
            ex_sql:=ex_sql|| _key || '='''||  (recs.value ->> 'feild_value')  || ''',';
        end if;


    end loop;
    ex_sql:= substring(ex_sql from 0 for length(ex_sql));

    --setting condition in where 
     ex_sql:=ex_sql||' where 1=1';
    for recs in select * from  json_array_elements(condition_feilds::json)  loop
        _key   := recs.value ->> 'feild_name';
        _value := recs.value ->> 'feild_value' ;

         if json_typeof(recs.value -> 'feild_value') ='number' then 
            ex_sql:=ex_sql|| ' and ' || _key || '=' ||  _value ||',';
        else 
            ex_sql:=ex_sql|| ' and ' || _key || '='''||  (recs.value ->> 'feild_value') || ''',';
        end if;
    end loop;
    ex_sql:= substring(ex_sql from 0 for length(ex_sql));
    return_value:=ex_sql;
end;
$$ language plpgsql;

當我將參數傳遞為：'test'時，'[{“ feild_name”：“ name”，“ feild_value”：“ ssqhan”}，{“ feild_name”：“ salary”，“ feild_value”：5200.00}]''，' [{“ feild_name”：“ id”，“ feild_value”：2}]'

返回SQL，如：update test set name ='ssqhan'，salary = 5200.00 where 1 = 1 and id = 2

是的，這就是我想要的，當數據類型是文本或數字時，這可能有效，但是如果數據類型是復合的？