Put value on everything null in mysql

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I have the following problem,I created a table in mysql added all the records and after that I created a foreign key in it, this table contains information of only one "thing", however in the future it will have more things. I wanted to know if there is a query that replaces everything that is Null by another value,it is no use to change the default because in the future this value will have to change

mysql
  • 3

    update tabelea set campo = 'outro valor' where campo is null. Not?

  • '-' oh God........

  • 1

    @Rafael, it was I who gave the -1 and I explain why: It does not present research effort. If you have something to argue, you are at ease

  • This is not the place nor the time. However, help more. Don’t just play -1. And if you are so sure of this, why did you withdraw?

2 answers

5

From what I understand you had something like this:

TabelaX
|--------------------|
| ColA | ColB | ColC |
|------|------|------|
| 1    | 'ab' |  3   |
| 2    | 'ac' |  3   |
| 3    | 'ad' |  5   |
|--------------------|

You have created a new column and the existing values are with NULL;

TabelaX
|---------------------------|
| ColA | ColB | ColC | ColD |
|------|------|------|------|
| 1    | 'ab' |  3   | null |
| 2    | 'ac' |  3   | null |
| 3    | 'ad' |  5   | null |
|---------------------------|

You want to change to a specific value, just use:

UPDATE TabelaX SET ColD = 1;

If you can’t, it may be that the database server has secure update mode enabled (i.e., you need a clause where to the update work), you could use 1=1 that will always be true and will update all records.

UPDATE TabelaX SET ColD = 1 WHERE 1=1;

Upshot:

TabelaX
|---------------------------|
| ColA | ColB | ColC | ColD |
|------|------|------|------|
| 1    | 'ab' |  3   |  1   |
| 2    | 'ac' |  3   |  1   |
| 3    | 'ad' |  5   |  1   |
|---------------------------|
  • 1

    It was that same friend, I had tried so but was with safe update mode, the second way worked. Obg

3

The command to update records is UPDATE, which has the following syntax:

UPDATE nome_tabela
SET CAMPO = "novo_valor"
WHERE campo is null

Do this when you need to update the fields that are null, which is your case.

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