UNION with 2 DATABASES, SQL

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UNION with 2 DATABASES, SQL

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#1 by (1 votes)
#2 by (1 votes)

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I need to integrate 2 TABLES from DB different into a same DGV .

I found several tutorials, but none that helped me from configuration to the connection, at least not the way I work with the connections.

Follow an ex. of what I call a Select:

MySqlConnection conexaoSLT = ClassConexao.DBEMG();

MySqlCommand _comando = new MySqlCommand(String.Format("SELECT * FROM tabel1 WHERE Carro = @tipoCarro"), conexaoSLT );

MySqlDataReader _reader = _comando.ExecuteReader();
_reader.Read();

....

How can I connect two databases to a SELECT UNION ?

sql sql-server

asked by anonymous 26.04.2017 / 15:37

2 answers

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score 1 · Answer 1

You should verify that the user you are using on your connection has read permission in the other database.

No SELECT should use the name of the other bank before the table reference.

Example:

SELECT C.NOMCLI, C.CODCLI, E.CODCLI FROM DB1.CLIENTES C, DB2.CLIENTES E

It may happen that in your databases you need to put the user before the name of the bank for example:

SELECT C.NOMCLI, C.CODCLI, E.CODCLI FROM USUARIO1.DB1.CLIENTES C, USUARIO 2.DB2.CLIENTES E

Rest to make UNION , WHERE E ETC, you only reference normally.

score 1 · Answer 2

As long as the user has permission on both banks.

Assuming it is SQL Server and the tables are the same on both banks:

SELECT * FROM OUTRO_BANCO..TABELA WHERE ..... 
UNION
SELECT * FROM ESSE_BANCO..TABELA WHERE .....

If the tables are different:

SELECT campo1, campo2, campo3 FROM OUTRO_BANCO..TABELA WHERE ..... 
UNION
SELECT campo1, campo2, campo3 FROM ESSE_BANCO..TABELA WHERE .....

If it's Oracle and the same tables:

SELECT * FROM OUTRO_BANCO.TABELA WHERE ..... 
UNION
SELECT * FROM ESSE_BANCO.TABELA WHERE .....

Oracle and different tables:

 SELECT campo1, campo2, campo3 FROM OUTRO_BANCO.TABELA WHERE ..... 
 UNION
 SELECT campo1, campo2, campo3 FROM ESSE_BANCO.TABELA WHERE .....