MySQL错误1064：存储过程

Question

thanks, It's work

It was on this 2 line :

SET valueName = CONCAT(valueName, ' ,', _valueSplit);
SET valueValue = CONCAT(valueValue,' ,', json(_entryData, _valueSplit));

I have declared the variable, but at NULL so CONCAT return NULL and the query go on NULL to

thanks to Devart for helping me

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the post :

when I try to use my Stored Procedure I have this error

call _extract() Error Code: 1064. You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'NULL' at line 1

but I see nothing in the procedure this my procedure, but no instruction NULL on it

CREATE PROCEDURE _extract()
BEGIN
    DECLARE _entryType VARCHAR(45);
    DECLARE _entryData VARCHAR(1024);
    DECLARE _entryTime BIGINT(20);

    DECLARE no_more_rows BOOLEAN;
    DECLARE num_rows INT DEFAULT 0;

    DECLARE entryCursor CURSOR FOR SELECT entryValue, entryTime FROM TrackingEntry;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET no_more_rows = TRUE;

    OPEN entryCursor;
    select FOUND_ROWS() into num_rows;

    mainLoop: LOOP

        FETCH entryCursor INTO _entryData, _entryTime;

        IF no_more_rows THEN
            CLOSE entryCursor;
            LEAVE mainLoop;
        END IF;

        SET _entryType = json(_entryData, "type");
        CALL split_string(json(_entryData, "data"), ",");
        CALL _extractJson(_entryType, _entryData);

    END LOOP mainLoop;
END$$

_extractJson procedure : the next part of the extration of the data

CREATE PROCEDURE _extractJson(`_entryType` VARCHAR(255))
BEGIN

    DECLARE _valueSplit VARCHAR(255);

    DECLARE valueName VARCHAR(255);
    DECLARE valueValue VARCHAR(255);

    DECLARE split_no_more_rows BOOLEAN;
    DECLARE split_num_rows INT DEFAULT 0;

    DECLARE splitCursor CURSOR FOR SELECT SQL_CALC_FOUND_ROWS _value FROM SplitValues;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET split_no_more_rows = TRUE;

    OPEN splitCursor;
    select FOUND_ROWS() into split_num_rows;
    dataLoop: LOOP
        FETCH splitCursor INTO _valueSplit;
        IF split_no_more_rows THEN
            CLOSE splitCursor;
            LEAVE dataLoop;
        END IF;

        SET valueName = CONCAT(valueName, ' ,', _valueSplit);
        SET valueValue = CONCAT(valueValue,' ,', json(_entryData, _valueSplit));

    END LOOP dataLoop;
    SET @query = CONCAT('INSERT INTO ',_entryType, ' (',valueName,') VALUES (',valueValue,')' );
    PREPARE stmt FROM @query;
    EXECUTE stmt;
    DEALLOCATE PREPARE stmt;
    --end stuffs here
END$$

to explain what i want to do

some Data are stored in trackingEntry, each row contain information about what the user do (in a social game) and where he come from (action, referer, and some other value)

theses data are stored in a Json format like that : { "type" : "tableName", "data" : "row1,row2,row3", "row1" : "value", "row2" : "value", "row3" : "value" }

the type of the data (the action (connection, publish on wall)) it's a table's name of one of our dashboard application

The "data" is the list of the available datas

and after we have the Datas

Answer 1

You have to add SQL_CALC_FOUND_ROWS in the select statement, so that the FOUND_ROWS() function works.

So change this line

DECLARE entryCursor CURSOR FOR SELECT entryValue, entryTime FROM TrackingEntry;

like this

DECLARE entryCursor CURSOR FOR SELECT SQL_CALC_FOUND_ROWS entryValue, entryTime FROM TrackingEntry;

You can read more about it here .

Answer 2

The problem can be with a prepared INSERT statement, it seems that one of the variables is NULL. Try to comment prepared statements and select @query, you will see the problem -

SET @query = CONCAT('INSERT INTO ',_entryType, ' (',valueName,') VALUES (',valueValue,')' );
SELECT @query;
-- PREPARE stmt FROM @query;
-- EXECUTE stmt;
-- DEALLOCATE PREPARE stmt;