Php 如何拆分每个逗号的列值？

我有一张这样的桌子：

-- mytable
+----+------------+
| id |   value    |
+----+------------+
| 1  | one,ten    |
| 2  | nine,two   |
| 3  | five, one  |
+----+------------+

-- expected result:
+----+-------+------+
| id | val1  | val2 |
+----+-------+------+
| 1  | one   | ten  |
| 2  | nine  | two  |
| 3  | five  | one  |
+----+-------+------+

-- query
SELECT id, value FROM mytable

-- then
$vals = explode(",", $rows['value']);
foreach($vals as $val){
  //do stuff
}

SELECT id,
       SUBSTRING_INDEX(value,',', 1) as val1,
       SUBSTRING_INDEX(value,',', -1) as val2
FROM mytable

value

列的值始终由两部分组成，这两部分与

，

组合在一起。现在我想在两个单独的列中选择它们，如下所示：

-- mytable
+----+------------+
| id |   value    |
+----+------------+
| 1  | one,ten    |
| 2  | nine,two   |
| 3  | five, one  |
+----+------------+

-- expected result:
+----+-------+------+
| id | val1  | val2 |
+----+-------+------+
| 1  | one   | ten  |
| 2  | nine  | two  |
| 3  | five  | one  |
+----+-------+------+

-- query
SELECT id, value FROM mytable

-- then
$vals = explode(",", $rows['value']);
foreach($vals as $val){
  //do stuff
}

SELECT id,
       SUBSTRING_INDEX(value,',', 1) as val1,
       SUBSTRING_INDEX(value,',', -1) as val2
FROM mytable

我该怎么做

---

我可以通过PHP这样做：

-- mytable
+----+------------+
| id |   value    |
+----+------------+
| 1  | one,ten    |
| 2  | nine,two   |
| 3  | five, one  |
+----+------------+

-- expected result:
+----+-------+------+
| id | val1  | val2 |
+----+-------+------+
| 1  | one   | ten  |
| 2  | nine  | two  |
| 3  | five  | one  |
+----+-------+------+

-- query
SELECT id, value FROM mytable

-- then
$vals = explode(",", $rows['value']);
foreach($vals as $val){
  //do stuff
}

SELECT id,
       SUBSTRING_INDEX(value,',', 1) as val1,
       SUBSTRING_INDEX(value,',', -1) as val2
FROM mytable

---

但是我想知道，我可以在mysql中这样做吗？

为此，您可以使用函数

INSTR（）

找到逗号的位置，然后使用

LEFT（）

和

RIGHT（）

将它们拆分为您需要的两列，如下所示：

SELECT id
,LEFT(value,INSTR(value,',')-1) AS val1
,RIGHT(value,CHAR_LENGTH(value)-INSTR(value,',')-1) AS val2
FROM mytable

---

可以使用

SUBSTRING\u索引（字符串、分隔符、计数）

这样做：

-- mytable
+----+------------+
| id |   value    |
+----+------------+
| 1  | one,ten    |
| 2  | nine,two   |
| 3  | five, one  |
+----+------------+

-- expected result:
+----+-------+------+
| id | val1  | val2 |
+----+-------+------+
| 1  | one   | ten  |
| 2  | nine  | two  |
| 3  | five  | one  |
+----+-------+------+

-- query
SELECT id, value FROM mytable

-- then
$vals = explode(",", $rows['value']);
foreach($vals as $val){
  //do stuff
}

SELECT id,
       SUBSTRING_INDEX(value,',', 1) as val1,
       SUBSTRING_INDEX(value,',', -1) as val2
FROM mytable

您的桌子设计为1NF。。解决这个问题first@Pரதீப் “1NF”是什么意思？而且这不是我的表的设计，它实际上是函数返回的内容。我必须组合它们，因为mysql函数只返回一个值。现在我需要把它们分开。我有一张像这样的表格。这句话引导我写评论。。INF表示将原子值存储在一列中，但不超过一个值。请参阅。