Impala - Get for all tables in database concentenated columns

问题

Lets say I have a database A with tables B1 and B2. B1 has columns C1 and C2

and B2 has columns D1, D2 and D3.

I am looking for an Impala query that yields the following desired output:

B1    | "C1+C2"

B2    | "D1+D2+D3"

where "D1+D2+D3" and "C1+C2" are concatenated strings.

回答1:

Do you want the concatenated columns in a new table? Or do you want to add the concatenated columns to your existing tables? Either way, you can use the code below in impala to concatenated columns:

SELECT 
CONCAT(C1,C2) AS concat_fields
, "B1" AS table_name
FROM B1
UNION
SELECT 
CONCAT(D1,D2,D3) AS concat_fields
, "B2" AS table_name
FROM B2

来源：https://stackoverflow.com/questions/49321946/impala-get-for-all-tables-in-database-concentenated-columns