相关疑难解决方法(0)

我想在Postgres函数中传递一个表名作为参数.我试过这段代码:

CREATE OR REPLACE FUNCTION some_f(param character varying) RETURNS integer 
AS $$
    BEGIN
    IF EXISTS (select * from quote_ident($1) where quote_ident($1).id=1) THEN
     return 1;
    END IF;
    return 0;
    END;
$$ LANGUAGE plpgsql;

select some_f('table_name');

我得到了这个:

ERROR:  syntax error at or near "."
LINE 4: ...elect * from quote_ident($1) where quote_ident($1).id=1)...
                                                             ^

********** Error **********

ERROR: syntax error at or near "."

以下是更改为此时出现的错误select * from quote_ident($1) tab where tab.id=1:

ERROR:  column tab.id does not exist
LINE 1: ...T EXISTS …

我写了一个函数,输出一个SELECT以文本形式组成的PostgreSQL 查询.现在我不想再输出文本,但实际上SELECT对数据库运行生成的语句并返回结果 - 就像查询本身一样.

到目前为止我所拥有的:

CREATE OR REPLACE FUNCTION data_of(integer)
  RETURNS text AS
$BODY$
DECLARE
   sensors varchar(100);   -- holds list of column names
   type    varchar(100);   -- holds name of table
   result  text;           -- holds SQL query
       -- declare more variables

BEGIN
      -- do some crazy stuff

      result := 'SELECT\r\nDatahora,' || sensors ||
      '\r\n\r\nFROM\r\n' || type ||
      '\r\n\r\nWHERE\r\id=' || $1 ||'\r\n\r\nORDER BY Datahora;';

      RETURN result;
END;
$BODY$
LANGUAGE 'plpgsql' VOLATILE;
ALTER FUNCTION data_of(integer) OWNER TO postgres;

sensors …

鉴于此类型:

-- Just for testing purposes:
CREATE TYPE testType as (name text)

我可以使用此函数动态获取字段的值:

CREATE OR REPLACE FUNCTION get_field(object anyelement, field text) RETURNS text as
$BODY$
DECLARE
    value text;
BEGIN
    EXECUTE 'SELECT $1."' || field || '"'
      USING object
       INTO value;

    return value;
END;
$BODY$
LANGUAGE plpgsql

呼叫get_field('(david)'::testType, 'name')按预期工作返回"大卫".

但是如何在复合类型中设置字段的值？我试过这些功能:

CREATE OR REPLACE FUNCTION set_field_try1(object anyelement, field text, value text)
RETURNS anyelement
as
$BODY$
DECLARE
    value text;
BEGIN
    EXECUTE '$1."' || field || '" := $2'
      USING object, value; …

原始表的规则存储在一个名为md_formula的表中，该表用于映射到目标表中

放置/创建/插入以下内容raw_dbs_transactiondetailscash：

DROP TABLE raw_dbs_transactiondetailscash

CREATE TABLE raw_dbs_transactiondetailscash(
    accountnumber VARCHAR(100),
    referencecurrency VARCHAR(100),
    transactiondate datetime)

INSERT INTO raw_dbs_transactiondetailscash(
    accountnumber, referencecurrency, transactiondate)
    SELECT 'XYZ','$','01/01/2016'            

放置/创建/插入以下内容md_formula：

DROP TABLE MD_Formula 

CREATE TABLE MD_Formula (
    Format VARCHAR(20),
    tbl_Src VARCHAR(200),
    Col_src VARCHAR(500),
    tbl_Des VARCHAR(200),
    Col_des VARCHAR(100),
    Condition VARCHAR(500) )

INSERT INTO md_formula(format, tbl_src, Col_src, tbl_des,Col_des)    
    SELECT 'Dbs','raw_dbs_transactiondetailscash','accountnumber',
            'normalized_transaction','account_number'
    UNION ALL
    SELECT 'Dbs','raw_dbs_transactiondetailscash','referencecurrency',
            'normalized_transaction','currency'
    UNION ALL
    SELECT 'Dbs','raw_dbs_transactiondetailscash','transactiondate',
            'normalized_transaction','trade_date'

从存储在md_Formula中的原始表中获取数据TSQL（例如，仅选择一列）

这实际上会执行

SELECT accountnumber
FROM raw_dbs_transactiondetailscash

并从raw_dbs_transactiondetailscash表中获取数据集

DECLARE @sql VARCHAR(100) …