这件事把我弄糊涂了，我希望解决办法是“你知道为什么这不管用，是不是？”式的回答。
下面是：通过php我调用了一个mysql存储过程，因此：

$sql = "CALL sp_test;";
$mysqli->query($sql);

没问题。我知道存储过程会被执行。
这是我为这个例子划分的存储过程，它仍然产生同样的问题。

DELIMITER \\
DROP PROCEDURE IF EXISTS sp_test\\

CREATE PROCEDURE sp_test()
DETERMINISTIC

BEGIN
DECLARE exit_loop TINYINT(1) DEFAULT 0;
DECLARE v_TableName VARCHAR(50); DECLARE v_ScanID INT(11); DECLARE v_ScanType TINYINT(4); 
    DECLARE v_TitleID INT(11); DECLARE v_VolumeNo INT(11); DECLARE v_IssueNo VARCHAR(10); DECLARE v_IssueDate INT(11); DECLARE v_FIDateUnknown TINYINT(4); DECLARE v_PureHavocScan TINYINT(4);

-- declare cursor for employee email
DECLARE storeroom_cursor CURSOR FOR SELECT TableName, ScanID, ScanType, FIDateUnknown, TitleID, VolumeNo, REPLACE(IssueNo, "\'", "") AS IssueNo, IssueDate FROM t_storeroom ts JOIN t_issueguide tig ON ts.TitleID = tig.ComicTitleID;

-- declare NOT FOUND handler
DECLARE CONTINUE HANDLER FOR NOT FOUND SET exit_loop = TRUE;

OPEN storeroom_cursor;

get_purehavoc: LOOP

    FETCH storeroom_cursor INTO v_TableName, v_ScanID, v_ScanType, v_FIDateUnknown, v_TitleID, v_VolumeNo, v_IssueNo, v_IssueDate;

    IF exit_loop = TRUE THEN 
        LEAVE get_purehavoc;
    END IF;

            CASE v_ScanType

                WHEN '1' AND v_FIDateUnknown = 0 THEN
                    SET @sql_text = CONCAT("SELECT @RowCount := COUNT(*) FROM ", v_TableName, " WHERE ComicTitleID = ", v_TitleID, " AND VolumeNo = ", v_VolumeNo, " AND IssueNo = '", v_IssueNo, "' AND IssueDate = ", v_IssueDate, " AND DiggerExclusive = 1;");

                WHEN '1' AND v_FIDateUnknown = 1 THEN
                    SET @sql_text = CONCAT("SELECT @RowCount := COUNT(*) FROM ", v_TableName, " WHERE ComicTitleID = ", v_TitleID, " AND VolumeNo = ", v_VolumeNo, " AND IssueNo = '", v_IssueNo, "' AND DiggerExclusive = 1;");

                -- WHEN '2' THEN
                    -- Do something

            END CASE;

            PREPARE statement FROM @sql_text;
            EXECUTE statement;  

            -- Setting the PureHavocScan variable to enter into the PREPARE STATEMENT.
            IF @RowCount = 0 THEN 
                SET @PureHavocScan = 1;
            ELSE                    
                SET @PureHavocScan = 0;
            END IF;

            SET @ScanID = v_ScanID;
            SET @TableName = v_TableName;

            -- SET @sql_text = concat("UPDATE t_storeroom SET PureHavocScan = ? WHERE TableName = ? AND ScanID = ? ");
            SET @sql_text = concat("UPDATE t_storeroom SET PureHavocScan = ", @PureHavocScan, " WHERE TableName = '", @TableName, "' AND ScanID = ", @ScanID, ";");
            PREPARE statement FROM @sql_text;
            EXECUTE statement;

END LOOP get_purehavoc;

DEALLOCATE PREPARE stmt;
CLOSE storeroom_cursor; 
END//
DELIMITER ;

当我在mysql数据库管理工具（在我的例子中是navicat）中运行这个存储过程时，存储过程100%按预期工作，所有应该更新的行都会得到更新。
但是，当我通过php运行这个存储过程时，只有1行（有时2行）得到更新。
以完全相同的方式调用的其他存储过程工作正常。就是这个。与失败的命令的唯一区别是mysql命令是一个更新，而selects和insert命令工作正常。
我已经做了两天了，已经用尽了我所有的知识。所以如果有人能帮我摆脱痛苦，我会非常感激的。