SQL 插入值列，其中值来自另一列

Question

I have a table like this in MySQL, and I want to add values into the kodeunik column where the value is a combination of Kode , Daerah and NomorKode

Expected output for kodeunik column:

Bank BCA       101    00   0003   101000003

Bank BCA PT    101    00   0003   101000001

Bank BNI       101    00   0003   101000004

Question:

1. How to query like that?

2. Is it possible to make the kodeunik as primary key?

Answer 1

There is no need to do this; you can simply generate the value on the fly:

SELECT *, CONCAT(Kode, Daerah, NomorKode) AS kodeunik
FROM yourTable

or create a VIEW :

CREATE VIEW yT_ke AS
    SELECT *, CONCAT(Kode, Daerah, NomorKode) AS kodeunik
    FROM yourTable;
SELECT * FROM yT_ke

Output (for both queries):

JenisPerkiraan  Kode    Daerah  NomorKode   kodeunik
Bank BCA        101     00      0003        101000003
Bank BCA PT     101     00      0001        101000001
Bank BNI        101     00      0004        101000004

If you want a primary key on this combined field, just add it over the 3 columns:

 ALTER TABLE yourTable ADD PRIMARY KEY (Kode, Daerah, NomorKode)

Demo on dbfiddle

Answer 2

1. You can use Update query to achieve it.

    UPDATE your_table_name
    SET kodeunik = concat(`Kode`, `Daerah`, 'NomorKode`)

2. If you make sure kodeunik value is unique, you can also make it as primary key.

Answer 3

Mysql has CONCAT() function. In your case, you can try:

select CONCAT(Kode, Daerah, NomorKode) from <your_table_name>;

If it is what you want, you can use subquery to update them.