Question

如何编写SQL查询以从表中选择行，其中where子句中的列将根据发送的内容具有不同的值。示例：发送的参数对于单个列名称具有3个不同的值。我如何检索满足所有参数的行。

Answer 1

您可以使用IN / NOT IN构造...

匹配参数中具有列值的所有列：

SELECT * FROM table WHERE `columnName` IN ('parameter1','parameter2','parameter3');

要匹配参数中没有列值的所有列：

SELECT * FROM table WHERE `columnName` NOT IN ('parameter1','parameter2','parameter3');

Answer 2

我认为你有很多不确定的潜在价值。

在这种情况下创建一个函数：

CREATE FUNCTION [dbo].[fnSplit](
    @sInputList VARCHAR(max) -- List of delimited items
  , @sDelimiter VARCHAR(5) -- delimiter that separates items
) RETURNS @List TABLE (item VARCHAR(max))

BEGIN
DECLARE @sItem VARCHAR(max)
WHILE CHARINDEX(@sDelimiter,@sInputList,0) <> 0
 BEGIN
 SELECT
  @sItem=RTRIM(LTRIM(SUBSTRING(@sInputList,1,CHARINDEX(@sDelimiter,@sInputList,0)-1))),
  @sInputList=RTRIM(LTRIM(SUBSTRING(@sInputList,CHARINDEX(@sDelimiter,@sInputList,0)+LEN(@sDelimiter),LEN(@sInputList))))

 IF LEN(@sItem) > 0
  INSERT INTO @List SELECT @sItem
 END

IF LEN(@sInputList) > 0
 INSERT INTO @List SELECT @sInputList -- Put the last item in
RETURN
END

您现在可以按以下方式编写查询：

SELECT * FROM myTable WHERE myColumn IN 
   (SELECT * FROM dbo.fnSplit(stringParamHere, stringSeparatorHere))

通过这种方式，您可以使用给定的分隔符在单个参数中传递x值列表。

以上示例用于分隔字符串值。然而，只需更改表项的类型并将“INSERT INTO ...”行更改为：

，就可以非常轻松地生成返回整数表的fnSplitInt。

INSERT INTO @List SELECT CAST(@sItem as int)

postgresql的相同功能如下：

CREATE OR REPLACE FUNCTION public.fnsplit(
    IN stringlist character varying,
    IN delimit character varying)
  RETURNS TABLE(items character varying) AS
$BODY$
declare remainderlist character varying;
declare front character varying;
declare delimitpos integer;
begin
    drop table if exists tmptbl;
    create temp table tmptbl(items character varying);
    remainderlist := $1;
    delimitpos := strpos(remainderlist, $2);
    while delimitpos > 0 loop
        front := trim(both from(left(remainderlist, delimitpos -1)));
        remainderlist := substr(remainderlist, delimitpos + 1);
        if length(front) > 0 then
            insert into tmptbl values (front);
        end if;
        delimitpos := strpos(remainderlist, $2);
    end loop;
    --insert last value
    remainderlist := trim(both from remainderlist);
    if length(remainderlist) > 0 then
        insert into tmptbl values (remainderlist);
    end if;
    return query
        select * from tmptbl;
        return;
end;
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100
  ROWS 1000;

HTH

Answer 3

尝试此选项以匹配大量值

    SELECT * FROM table WHERE columnName IN (select 
unnest(regexp_split_to_array(comma_separated_values::text, ',')));

或者你也可以用Function作为输入参数写一个comma_separated_values，如

CREATE OR REPLACE FUNCTION myFunction(comma_separated_values Text)
  RETURNS refcursor AS

$BODY$
DECLARE
cur_data refcursor;

begin
open cur_data for
 SELECT * FROM table WHERE columnName IN (select 
    unnest(regexp_split_to_array(comma_separated_values::text, ',')));
  return cur_data ;
end;

$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;

编辑：您可以使用text array创建另一个函数input 参数

 CREATE OR REPLACE FUNCTION myFunction(values Text[])
      RETURNS refcursor AS

    $BODY$
    DECLARE
    cur_data refcursor;

    begin
    open cur_data for
     SELECT * FROM table WHERE columnName IN (select unnest(values));
      return cur_data ;
    end;

    $BODY$
      LANGUAGE plpgsql VOLATILE
      COST 100;

希望它有所帮助。

查询选择具有不同单列值的行

3 个答案: