mysql - 每行具有不同值的 UPDATE SET 列

Question

如果我有一张 table my_table像这样:

| id | val1 | val2|
| 1  | foo1 | bar |
| 2  | foo2 | baz |
| 3  | foo3 | bam |

我有一个以编程方式生成的硬编码逗号分隔值列表:spam, eggs, ham .

我想将我的值插入列 val1 .我在想象这样的事情:
UPDATE my_table SET val1 = SELECT * FROM (VALUES ('spam'),('eggs'),('ham'))
但这给了我一个语法错误(MySQL 5.6.44)

最终结果应如下所示:

| id | val1 | val2|
| 1  | spam | bar |
| 2  | eggs | baz |
| 3  | ham  | bam |

Answer 1

DROP TABLE IF EXISTS my_table;

CREATE TABLE my_table
(id SERIAL PRIMARY KEY
,val1 VARCHAR(12) NOT NULL
,val2 VARCHAR(12) NOT NULL
);

INSERT INTO my_table VALUES
(1,'foo1','bar'),
(2,'foo2','baz'),
(3,'foo3','bam');

UPDATE my_table SET val1 = SUBSTRING_INDEX(SUBSTRING_INDEX('spam,eggs,ham',',',id),',',-1);

SELECT * FROM my_table;
+----+------+------+
| id | val1 | val2 |
+----+------+------+
|  1 | spam | bar  |
|  2 | eggs | baz  |
|  3 | ham  | bam  |
+----+------+------+