Question

我有一个查询INSERT值INTO表'material_weight'

这里是：

$sql_material = "INSERT INTO `material_weight`
    (mat_record_id, material_weight, material_name)
    VALUES
    ((select MAX(record_id) FROM truck_records), '$material_wei_1', '$material_1'), 
    ((select MAX(record_id) FROM truck_records), '$material_wei_2', '$material_2'), 
    ((select MAX(record_id) FROM truck_records), '$material_wei_3', '$material_3'), 
    ((select MAX(record_id) FROM truck_records), '$material_wei_4', '$material_4'), 
    ((select MAX(record_id) FROM truck_records), '$material_wei_5', '$material_5'), 
    ((select MAX(record_id) FROM truck_records), '$material_wei_6', '$material_6'), 
    ((select MAX(record_id) FROM truck_records), '$material_wei_7', '$material_7'), 
    ((select MAX(record_id) FROM truck_records), '$material_wei_8', '$material_8'), 
    ((select MAX(record_id) FROM truck_records), '$material_wei_9', '$material_9'), 
    ((select MAX(record_id) FROM truck_records), '$material_wei_10', '$material_10')    ";

我想要一个if语句，IF $ material_wei_1或$ material_wei_2 ...等于零，不要插入此行。

我试着理解IF语法，但没有运气，这就是我试过的......

$sql_material = "INSERT INTO `material_weight`
    (mat_record_id, material_weight,    material_name)
    VALUES
    ((select MAX(record_id) FROM truck_records), '$material_wei_1', '$material_1'), 

    if( '$material_wei_2' = 0, ((select MAX(record_id) FROM truck_records), '$material_wei_2', '$material_2') , ),

    ((select MAX(record_id) FROM truck_records), '$material_wei_3', '$material_3'),...

IF语法有问题吗？

Answer 1

您将这些值作为参数传递给查询。所以我的第一反应是修复应用程序。

但是，您可以在查询中执行此操作。使用子查询将参数组合在一起，只需在外部查询中使用WHERE子句。

以下查询执行此操作还会过滤掉重复的子查询，因此这应该比原始版本更快：

INSERT INTO material_weight (mat_record_id, material_weight, material_name)
    SELECT mat_record_id, material_weight, material_name
    FROM ((SELECT '$material_wei_1' as material_weight, '$material_1' as material_name) UNION ALL
          (SELECT '$material_wei_2' as material_weight, '$material_2' as material_name) UNION ALL
          . . .
         ) m CROSS JOIN  
         (SELECT MAX(record_id) as mat_record_id FROM truck_records) tr
    WHERE material_weight > 0;

sql - php查询，如果特定列为零则不要INSERT

1 个答案: