[英]How to copy text column value from one row to another row in mySQL
I have table pref having column value. 我有表pref有列值。 This value has type text.
该值具有类型文本。 I want copy the value field value of row with id 7 to the value field of row with id 1. Can you please help how to do this.
我想将id为7的行的值字段值复制到id为1的行的值字段。能否请您帮忙完成此操作。 I know MS SQL, but I am new to mySQL.
我知道MS SQL,但我是mySQL的新手。
create table pref
(
id int,
value text
)
In MySQL you can't use a subselect from the same table you are updating, but you can use a join. 在MySQL中,您不能使用要更新的同一个表中的子选择,但可以使用连接。
UPDATE pref AS target
LEFT JOIN pref AS source ON source.id = 7
SET target.value = source.value
WHERE target.id = 1;
UPDATE
pref
SET
value = (SELECT value WHERE id = 7)
WHERE
id = 1
In my case, I was trying to copy an encrypted value from one row into an empty field in another row in the same table. 在我的例子中,我试图将一行中的加密值复制到同一个表中另一行的空字段中。 In this case, I needed to copy john's PIN into Jane's PIN.
在这种情况下,我需要将约翰的PIN复制到Jane的PIN中。
@mohang has it right. @mohang说得对。 Here is my adaptation :)
这是我的改编:)
name pin
john sdhjduwhdowodw7d87e838g83g8g3of...
jane
//copy from field with value into empty field
UPDATE my_table AS target
LEFT JOIN my_table AS source ON source.pin != ""
SET target.pin = source.pin
WHERE target.pin = "";
// Hurray, it works!
name pin
john sdhjduwhdowodw7d87e838g83g8g3of...
jane sdhjduwhdowodw7d87e838g83g8g3of...
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