Сплит-строки с использованием mysql

Я хочу создать хранимую процедуру, которая будет выполнять сопоставление двух таблиц. Мое требование состоит в том, чтобы сопоставить две таблицы на основе пользовательских пропусков столбцов в качестве входных данных.

Синтаксис:

CREATE PROCEDURE reconcile.matchTables(
  IN TAB1 VARCHAR(25), 
  IN TAB1 VARCHAR(25), 
  IN COLS1 VARCHAR(250) , 
  IN COLS2 VARCHAR(250))

EX:

matchTables('table1', 'table2', 'col1#col2#col3#col4' , 'col2#col13#col1#col8')

Теперь хранимая процедура должна сформировать предложение where, как показано ниже.

table1.col1 = table2.col2 
  and table1.col2 = table2.col13 
  and table1.col3 = table2.col1 
  and table1.col4 = table2.col8

Ответ 1

MySQL не включает функцию для разделения строки с разделителями. Однако его очень легко создать свою собственную функцию.

Функция определения пользователя:

CREATE [AGGREGATE] FUNCTION function_name
RETURNS {STRING|INTEGER|REAL|DECIMAL}

Функции:

CREATE FUNCTION SPLIT_STR(
  x VARCHAR(255),
  delim VARCHAR(12),
  pos INT
)
RETURNS VARCHAR(255)
RETURN REPLACE(SUBSTRING(SUBSTRING_INDEX(x, delim, pos),
       LENGTH(SUBSTRING_INDEX(x, delim, pos -1)) + 1),
       delim, '');

Использование:

SELECT SPLIT_STR(string, delimiter, position)

Ответ 2

Ответ

Таблица 1

CREATE TABLE `Table1` (
  `Col1` varchar(100) DEFAULT NULL,
  `Col2` varchar(100) DEFAULT NULL,
  `Col3` varchar(100) DEFAULT NULL,
  `Col4` varchar(100) DEFAULT NULL,
  `DummyColumn` varchar(45) DEFAULT NULL
)

Таблица 2

CREATE TABLE `Table2` (
  `col2` varchar(100) DEFAULT NULL,
  `col13` varchar(100) DEFAULT NULL,
  `col1` varchar(100) DEFAULT NULL,
  `col8` varchar(100) DEFAULT NULL
)

Сохраненная процедура

CREATE DEFINER=`Connect7827`@`%` PROCEDURE `reconcile.matchTables`(
 IN TAB1 VARCHAR(25), 
  IN TAB2 VARCHAR(25), 
  IN COLS1 VARCHAR(250) , 
  IN COLS2 VARCHAR(250))
StartfromHere: BEGIN


        DECLARE NoOfColumnInTable1  INT unsigned DEFAULT 0;   
        DECLARE NoOfColumnInTable2 INT unsigned DEFAULT 0;
        Declare Column1Count int default 1;
        Declare Column2Count int default 1;
        Declare vPickOneValue varchar(100);
        Declare querystring varchar(8000);
        Declare NoOFRowsInFinalResult int default 1;
        Declare _Tab1 varchar(1000);
        Declare _TAB2 varchar(1000);
        Declare _COLS1 varchar(1000);
        Declare _COLS2 varchar(1000);


        -- Column Names for Table 1 
        DROP TEMPORARY TABLE IF EXISTS Table1_Columns;
        CREATE TEMPORARY TABLE Table1_Columns(Column_Name varchar(100));
        SET @buffer= CONCAT_WS('','insert into Table1_Columns(Column_Name)
        SELECT COLUMN_NAME
        FROM INFORMATION_SCHEMA.COLUMNS
        WHERE table_name = ',"'",TAB1,"'");
        -- Select @buffer;
        PREPARE stmt FROM @buffer;
        EXECUTE stmt;
        -- Column Names for Table 2 
        DROP TEMPORARY TABLE IF EXISTS Table2_Columns;
        CREATE TEMPORARY TABLE Table2_Columns(Column_Name varchar(100));
        SET @buffer= CONCAT_WS('','insert into Table2_Columns(Column_Name)
        SELECT COLUMN_NAME
        FROM INFORMATION_SCHEMA.COLUMNS
        WHERE table_name = ',"'",TAB2,"'");
        -- Select @buffer;
        PREPARE stmt FROM @buffer;
        EXECUTE stmt;

        Set NoOfColumnInTable1=(Select count(*) from Table1_Columns);
        Set NoOfColumnInTable2=(Select count(*) from Table2_Columns);

        --    Select NoOfColumnInTable1,NoOfColumnInTable2;
        if (NoOfColumnInTable1=0) then
            Select 'Table 1 not found in database'as'Result';
            leave StartfromHere;
        end if;
        if (NoOfColumnInTable2=0) then
            Select 'Table 2 not found in database' as'Result' ;
            leave StartfromHere;
        end if;
        IF (NoOfColumnInTable1!=NoOfColumnInTable2) then
            Select 'No of column to be joined must be equal.'as'Result';
            leave StartfromHere;
        end if; 

        DROP TEMPORARY TABLE IF EXISTS BasedOn_Col1_List;
        CREATE TEMPORARY TABLE BasedOn_Col1_List(ID int NOT NULL AUTO_INCREMENT, Column_Name varchar(100), PRIMARY KEY (id));
        while Column1Count< NoOfColumnInTable1+1 do
               set @Query=CONCAT_WS('' ,"insert into BasedOn_Col1_List(Column_Name) Select SUBSTRING_Index('",COLS1,"','#',",Column1Count,");");
               -- Select @Query as'Value';
                PREPARE stmt1 FROM @Query;
                EXECUTE stmt1;
                SET Column1Count=Column1Count+1;
        end while;
        SET Column1Count=1;
        WHILE Column1Count<=NoOfColumnInTable1 do 
            SET vPickOneValue=(Select Concat(Column_Name,"#") from BasedOn_Col1_List where ID=Column1Count);
            update BasedOn_Col1_List set Column_Name=replace(Column_Name,vPickOneValue,"") where ID<>Column1Count;
            -- Select  vPickOneValue;
            SET Column1Count=Column1Count+1 ;
        end while;

        --   Preapre Table from Column2 Parameter
        DROP TEMPORARY TABLE IF EXISTS BasedOn_Col2_List;
        CREATE TEMPORARY TABLE BasedOn_Col2_List(ID int NOT NULL AUTO_INCREMENT, Column_Name varchar(100), PRIMARY KEY (id));
        while Column2Count< NoOfColumnInTable2+1 do
               set @Query=CONCAT_WS('' ,"insert into BasedOn_Col2_List(Column_Name) Select SUBSTRING_Index('",COLS2,"','#',",Column2Count,");");
               -- Select @Query as'Value';
                PREPARE stmt2 FROM @Query;
                EXECUTE stmt2;
                SET Column2Count=Column2Count+1;
        end while;
        SET Column2Count=1;
        WHILE Column2Count<=NoOfColumnInTable2 do 
            SET vPickOneValue=(Select Concat(Column_Name,"#") from BasedOn_Col2_List where ID=Column2Count);
            update BasedOn_Col2_List set Column_Name=replace(Column_Name,vPickOneValue,"") where ID<>Column2Count;
            -- Select  vPickOneValue;
            SET Column2Count=Column2Count+1 ;
        end while;

        DROP TEMPORARY TABLE IF EXISTS TableFromColumnList;
        CREATE TEMPORARY TABLE TableFromColumnList
                    (    ID int NOT NULL AUTO_INCREMENT, 
                        Table1Name varchar(100),
                        Column_Name_Table1 varchar(100), 
                        Table2Name varchar(1000), 
                        Column_Name_Table2 varchar(100), 
                        PRIMARY KEY (id)
                    );
        Insert into TableFromColumnList(Column_Name_Table1,Column_Name_Table2,Table1Name,Table2Name)    
        select    t1.Column_Name,t2.Column_Name,TAB1,TAB2
        from BasedOn_Col1_List t1 , BasedOn_Col2_List t2  where t1.Id=t2.id;        


        -- -- Preparing the final Result ----------------
        While NoOFRowsInFinalResult<=NoOfColumnInTable2 do -- / Or NoOFRowsInFinalResult<=NoOfColumnInTable2 --

            SET _Tab1  =(Select Table1Name from TableFromColumnList where Id=NoOFRowsInFinalResult);
            SET _COLS1  =(Select Column_Name_Table1 from TableFromColumnList where Id=NoOFRowsInFinalResult);
            SET _TAB2 =(Select Table2Name from TableFromColumnList where Id=NoOFRowsInFinalResult);
            SET _COLS2 =(Select Column_Name_Table2 from TableFromColumnList where Id=NoOFRowsInFinalResult);

            IF NoOFRowsInFinalResult=1 then
                SET querystring =concat_ws("" , querystring,_Tab1,".", _COLS1 , "=",_Tab2,".", _COLS2,"   ");
            else
                SET querystring =concat_ws("" , querystring ,"and",_Tab1,".", _COLS1 , "=" ,_Tab2,".", _COLS2 ,"   ");
            end if;

            SET NoOFRowsInFinalResult=NoOFRowsInFinalResult+1 ;
        End while;
        SET querystring=concat_ws("","Select * from ",TAB1,", "  ,TAB2," where ",querystring);
        Select querystring;

END

Ответ 3

CREATE PROCEDURE matchTables
@TAB1 VARCHAR(25), 
@TAB2 VARCHAR(25), 
@COLS1 VARCHAR(250) , 
@COLS2 VARCHAR(250)

AS


BEGIN
DECLARE @WHEREstring VARCHAR(MAX)
SET @WHEREstring = 
'   
WHERE
        ' 
SELECT @WHEREstring = @WHEREstring + @TAB1 +'.'+ tab1.col+' = '[email protected]+'.' + tab2.col +' AND
        ' 
            FROM
            (
                SELECT QUOTENAME(split.a.value('.','VARCHAR(100)')) AS col, ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) AS RowNum
                    FROM 
                    (
                        SELECT Cast ('<M>' + Replace(@COLS1, '#', '</M><M>')+ '</M>' AS XML) AS Tab1Data
                    ) AS A 
                    CROSS apply Tab1Data.nodes ('/M') AS Split(a)
            ) tab1
            INNER JOIN
            (
                Select QUOTENAME(AliasSplit.c.value('.', 'varchar(100)')) AS col, ROW_NUMBER() OVER(ORDER BY (SELECT NULL)) AS RowNum
                FROM 
                (
                    SELECT Cast ('<A>' + Replace(@COLS2, '#', '</A><A>')+ '</A>' AS XML) AS Tab2Data
                ) AS A 
                CROSS apply Tab2Data.nodes ('/A') AS AliasSplit(c)
            ) tab2
            ON tab1.RowNum = tab2.RowNum
        SET @WHEREstring= LEFT(@WHEREstring, LEN(@WHEREstring) - 8)

        print @WHEREstring
END

Теперь запустите его, используя:

 EXEC matchTables 'table1', 'table2', 'col1#col2#col3#col4' , 'col2#col13#col1#col8'

Надеюсь, вы получили желаемое предложение where. приветствия

Ответ 4

Вы можете создать свою собственную функцию:

CREATE FUNCTION String_split(inp VARCHAR(255),del VARCHAR(255),loc INT)
RETURNS VARCHAR(255)
RETURN REPLACE(Substring(Substring_index(inp, del,loc),LENGTH(Substring_index(inp, del, loc-1)) + 1),del, '');

Ответ 5

Нет никакой функции для разбиения строки. Вы можете сделать следующее:

DROP PROCEDURE IF EXISTS matchTables;
DELIMITER |
CREATE PROCEDURE matchTables(
    IN TAB1 VARCHAR(25), 
    IN TAB2 VARCHAR(25), 
    IN COLS1 VARCHAR(250), 
    IN COLS2 VARCHAR(250)
)
BEGIN
    SET @col1Values = COLS1;
    SET @col2Values = COLS2;
    SET @whereClause = ' WHERE ';
    SET @anotherCondition = '';

    WHILE (LOCATE('#', @col1Values) > 0)
    DO
        SET @value1 = SUBSTRING(@col1Values, 1, LOCATE('#', @col1Values) - 1);
        SET @value2 = SUBSTRING(@col2Values, 1, LOCATE('#', @col2Values) - 1);
        SET @col1Values = SUBSTRING(@col1Values, LOCATE('#', @col1Values) + 1);
        SET @col2Values = SUBSTRING(@col2Values, LOCATE('#', @col2Values) + 1);

        SET @whereClause = CONCAT(@whereClause, @anotherCondition, TAB1, '.', @value1, ' = ', TAB2, '.', @value2, ' ');
        SET @anotherCondition = ' AND ';
    END WHILE;

    SET @value1 = SUBSTRING(@col1Values, 1, LENGTH(@col1Values));
    SET @value2 = SUBSTRING(@col2Values, 1, LENGTH(@col2Values));
    SET @whereClause = CONCAT(@whereClause, @anotherCondition, TAB1, '.', @value1, ' = ', TAB2, '.', @value2, ' ');

    SET @qry = CONCAT('SELECT * FROM ', TAB1, ', ', TAB2, @whereClause);
    PREPARE stmt1 FROM @qry;
    EXECUTE stmt1;
    DEALLOCATE PREPARE stmt1;

END|
DELIMITER ;

Ответ 6

CHAR_LENGTH - вернуть правильную длину в символах

CREATE FUNCTION SPLIT_STR(
  x VARCHAR(255),
  delim VARCHAR(12),
  pos INT
)
RETURNS VARCHAR(255)
RETURN REPLACE(SUBSTRING(SUBSTRING_INDEX(x, delim, pos),
       CHAR_LENGTH(SUBSTRING_INDEX(x, delim, pos -1)) + 1),
       delim, '');