如果参数为 'NOT PASSED' postgresql，如何避免 'where' 子句中的列

Question

运行查询：

select * from employee where name = and age = and salary = ;

问题查询：

select * from employee where name = and age = ;

我怎样才能写出这样的逻辑 /* 如果 $3 被通过则 (and salary = ) */

注 : /* 我不能 check For null or Empty as $3 如未通过，则 $3 将无法用于 check*/

在 Node 中我是这样使用的

        postGresAdaptor.executeQueryWithParameters(QUERY, QUERYPARAMS, function(error, result) {
            if (error) {
                callback(error);
            } else {                    
                data = result.data;                    
            }
        });

不想在节点代码中添加逻辑，因为途中会有很多查询。

Answer 1

不太清楚你所说的是什么意思被传递，但也许你的意思是</code>是一个可选参数，<code>没有意义: 不在乎 ?

SELECT *
FROM employee
WHERE name = 
AND age = 
AND (  IS NULL OR salary = )
   ;

一些数据：

CREATE TABLE employee
        ( name varchar NOT NULL PRIMARY KEY
        , age integer
        , salary integer
        );

INSERT INTO employee ( name , age , salary ) VALUES
 ( 'Alice' , 13 , 3 )
,( 'Bob' , 11 , 5 )
,( 'Charlotte' , 15 , 9 )
,( 'David' , 17 , 10 )
        ;

与准备好的查询相同：

PREPARE qry (text, integer , integer) AS
SELECT *
FROM employee
WHERE name = 
AND age = 
AND (  IS NULL OR salary = )
   ;

    -- and call the prepared statement:
EXECUTE qry ('Alice', 13, 3);
EXECUTE qry ('Alice', 13, NULL);

输出：

CREATE TABLE
INSERT 0 4
PREPARE
 name  | age | salary 
-------+-----+--------
 Alice |  13 |      3
(1 row)

 name  | age | salary 
-------+-----+--------
 Alice |  13 |      3
(1 row)

Answer 2

您可以使用 default 参数类型，例如：

CREATE OR REPLACE FUNCTION _my_function(_name character varying, _age integer, _salary integer default NULL)
  RETURNS character varying AS
$BODY$
    begin

    if (_salary IS NULL) then

       select * from employee where name = _name and age = _age ;
    else
       select * from employee where name = _name and age = _age and salary =  _salary;
    end IF;
        return 'OK';

end;$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;

如果参数为 'NOT PASSED' postgresql，如何避免 'where' 子句中的列

how to avoid column in 'where' clause if parameter is 'NOT PASSED' postgresql

sql

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where-clause

node.js