使用临时 table 数据填充一组变量

Question

我开始创建一个 MySQL 程序来模拟 Risk 中的攻击和防御骰子游戏！游戏。该程序将攻击者和防御者的军队数量（由骰子表示）作为输入参数，然后掷骰子和 returns 在战斗中幸存的军队数量。攻击方和防御方各自打出自己的骰子，然后按降序排列，然后逐对比较，将具有最高值的攻击骰子与具有最高值的防御骰子进行比较，然后对其他骰子进行相同的操作（如果可用）。我通过将结果放在两个临时表中对骰子进行排序，然后使用 ALTER TABLE attack_table, ORDER BY dice, DESC 对它们进行排序，但现在我不知道如何填充返回变量

var_dice_1_attack
var_dice_2_attack
var_dice_3_attack
var_dice_1_defense
var_dice_2_defense
var_dice_3_defense

密码是

CREATE PROCEDURE IF NOT EXISTS `risk`.`play_dices`(INOUT attack INT, INOUT defense INT)
BEGIN
    DECLARE var_dice_1_attack INT;
    DECLARE var_dice_2_attack INT;
    DECLARE var_dice_3_attack INT;
    DECLARE var_dice_1_defense INT;
    DECLARE var_dice_2_defense INT;
    DECLARE var_dice_3_defense INT;
    
    CREATE TEMPORARY TABLE attack_table (dice INT NOT NULL);
    CREATE TEMPORARY TABLE defense_table (dice INT NOT NULL);
    
    -- FLOOR(RAND() * (<max> - <min> + 1)) + <min>
    -- generates a number between <min> and <max> inclusive 
    CASE attack
        WHEN '1' THEN
            SET var_dice_1_attack = FLOOR(RAND() * 6) + 1;
            INSERT INTO attack_table (dice) VALUE (var_dice_1_attack);
        WHEN '2' THEN
            SET var_dice_1_attack = FLOOR(RAND() * 6) + 1;
            SET var_dice_2_attack = FLOOR(RAND() * 6) + 1;
            INSERT INTO attack_table (dice) VALUE (var_dice_1_attack);
            INSERT INTO attack_table (dice) VALUE (var_dice_2_attack);
        WHEN '3' THEN
            SET var_dice_1_attack = FLOOR(RAND() * 6) + 1;
            SET var_dice_2_attack = FLOOR(RAND() * 6) + 1;
            SET var_dice_3_attack = FLOOR(RAND() * 6) + 1;
            INSERT INTO attack_table (dice) VALUE (var_dice_1_attack);
            INSERT INTO attack_table (dice) VALUE (var_dice_2_attack);
            INSERT INTO attack_table (dice) VALUE (var_dice_3_attack);
    END CASE;
    
    ALTER TABLE attack_table, ORDER BY dice, DESC;
    
    CASE defense
        WHEN '1' THEN
            SET var_dice_1_defense = FLOOR(RAND() * 6) + 1;
            INSERT INTO defense_table (dice) VALUE (var_dice_1_defense);
        WHEN '2' THEN
            SET var_dice_1_defense = FLOOR(RAND() * 6) + 1;
            SET var_dice_2_defense = FLOOR(RAND() * 6) + 1;
            INSERT INTO defense_table (dice) VALUE (var_dice_1_defense);
            INSERT INTO defense_table (dice) VALUE (var_dice_2_defense);
        WHEN '3' THEN
            SET var_dice_1_defense = FLOOR(RAND() * 6) + 1;
            SET var_dice_2_defense = FLOOR(RAND() * 6) + 1;
            SET var_dice_3_defense = FLOOR(RAND() * 6) + 1;
            INSERT INTO defense_table (dice) VALUE (var_dice_1_defense);
            INSERT INTO defense_table (dice) VALUE (var_dice_2_defense);
            INSERT INTO defense_table (dice) VALUE (var_dice_3_defense);
    END CASE;
    
    ALTER TABLE defense_table, ORDER BY dice, DESC;

为了信息的完整性，我也攻击了运行攻击和防御骰子之间比较的代码

IF (var_dice_1_attack IS NOT NULL) AND (var_dice_1_defense IS NOT NULL) THEN
    IF var_dice_1_attack > var_dice_1_defense THEN
        SET defense = defense - 1;
        IF defense < 0 THEN
            signal sqlstate '45003' set message_text = "Error, number of defense armies is negative";
        END IF;
    ELSEIF var_dice_1_attack <= var_dice_1_defense THEN
        SET attack = attack - 1;
        IF attack < 0 THEN
            signal sqlstate '45003' set message_text = "Error, number of attack armies is negative";
        END IF;
    END IF;
END IF;
IF (var_dice_2_attack IS NOT NULL) AND (var_dice_2_defense IS NOT NULL) THEN
    IF var_dice_2_attack > var_dice_2_defense THEN
        SET defense = defense - 1;
        IF defense < 0 THEN
            signal sqlstate '45003' set message_text = "Error, number of defense armies is negative";
        END IF;
    ELSEIF var_dice_2_attack <= var_dice_2_defense THEN
        SET attack = attack - 1;
        IF attack < 0 THEN
            signal sqlstate '45003' set message_text = "Error, number of attack armies is negative";
        END IF;
    END IF;
END IF;
IF (var_dice_3_attack IS NOT NULL) AND (var_dice_3_defense IS NOT NULL) THEN
    IF var_dice_3_attack > var_dice_3_defense THEN
        SET defense = defense - 1;
        IF defense < 0 THEN
            signal sqlstate '45003' set message_text = "Error, number of defense armies is negative";
        END IF;
    ELSEIF var_dice_3_attack <= var_dice_3_defense THEN
        SET attack = attack - 1;
        IF attack < 0 THEN
            signal sqlstate '45003' set message_text = "Error, number of attack armies is negative";
        END IF;
    END IF;
END IF;

DROP TEMPORARY TABLE attack_table;
DROP TEMPORARY TABLE defense_table;

END

Answer 1

您可以在执行 ALTER TABLE ... ORDER BY dice DESC; 之后添加此内容：

    ALTER TABLE attack_table ORDER BY dice DESC;

CASE attack
    WHEN '1' THEN
        SET var_dice_1_attack = (SELECT dice FROM attack_table  limit 1);
    WHEN '2' THEN
        SET var_dice_1_attack = (SELECT dice FROM attack_table  limit 1);
        SET var_dice_2_attack = (SELECT dice FROM attack_table  limit 1,1);
    WHEN '3' THEN
        SET var_dice_1_attack = (SELECT dice FROM attack_table  limit 1);
        SET var_dice_2_attack = (SELECT dice FROM attack_table  limit 1,1);
        SET var_dice_3_attack = (SELECT dice FROM attack_table  limit 2,1);
END CASE;

对防御骰子变量做同样的事情。

fiddle

使用临时 table 数据填充一组变量

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