mysql更新或插入多个记录(如果表中尚不存在) [英] mysql update or insert multiple records if not already exists in a table

问题描述

在mysql数据库中有一个名为"inventory_item"的表. "id"，"product_id"和"quantity"是表的列. "id"是主键，当插入记录时会自动生成.

there is a table named "inventory_item" in a mysql database. "id", "product_id" and "quantity" are columns of the table. "id" is the primary key and auto generate when a record is inserted.

当用户提交要在表中插入多条记录的表单时，可以在foreach循环中收集product_ids的所有数据及其数量.

when the user submit the form which is to insert multiple records to the table all the data of product_ids and their quantities can be collected in foreach loop.

所以我需要同时插入多个记录，并且仅当表中已经存在"product_id"而不要作为新记录插入时才应该更新数量.

so i need to insert multiple records at the same time and should only update quantity if "product_id" is already exist in the table without inserting as a new record.

这是我的代码块.

foreach ($dataArray as $value) { 
    $pcid = $value["pcid"];
    $quantity = $value["quantity"];
    $sql = "
        UPDATE table.inventory_item
        SET quantity='$quantity'
        WHERE product_category_id='$pcid'
        IF ROW_COUNT()=0
        INSERT INTO table.inventory_item
            (product_category_id, quantity)
        VALUES ('$pcid', '$quantity')
    ";
    $result = $conn->query($sql);
    var_dump($result);
}

推荐答案

插入.....在重复键上.... 和您的朋友.通过这种组合，您可以插入新记录或更新现有记录.为此，有必要在一个字段上定义一个唯一键，例如:示例中的 product_category_id

INSERT INTO ..... ON DUPLICATE KEY .... ist your friend. with this combination you can insert new records or update exiting records. for this it is necessary to have a unique key on a field that define your row like: product_category_id in your sample

*具有唯一键的表**

*a table with unique Key**

CREATE TABLE `table` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `product_id` varchar(32) CHARACTER SET latin1 DEFAULT NULL,
  `quantity` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `product_id` (`product_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

样品

mysql> select * from `table`;
Empty set (0,00 sec)

mysql> INSERT into `table` (product_id,quantity) Values ('p1',9),('p2',13) ON DUPLICATE KEY UPDATE quantity=VALUES(quantity);
Query OK, 2 rows affected (0,01 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> select * from `table`;
+----+------------+----------+
| id | product_id | quantity |
+----+------------+----------+
|  9 | p1         |        9 |
| 10 | p2         |       13 |
+----+------------+----------+
2 rows in set (0,00 sec)

mysql> INSERT into `table` (product_id,quantity) Values ('p3',9),('p2',15) ON DUPLICATE KEY UPDATE quantity=VALUES(quantity);
Query OK, 3 rows affected (0,00 sec)
Records: 2  Duplicates: 1  Warnings: 0

mysql> select * from `table`;
+----+------------+----------+
| id | product_id | quantity |
+----+------------+----------+
|  9 | p1         |        9 |
| 10 | p2         |       15 |
| 11 | p3         |        9 |
+----+------------+----------+
3 rows in set (0,00 sec)

mysql>

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