将Oracle与MSSQL表连接

Question

When i execute following line i get the result:

select * from my_table@link; 

But when i try to join linked table with other tables like in select i get error that says "z.id - invalid identifier"

SELECT

                e.USER_NAME,e.FULL_NAME,r.RFC_NUMBER,r.TYPE, 

                TO_CHAR(TRUNC(a.TOTAL_TIME/3600),'FM9900') || ':' ||
                TO_CHAR(TRUNC(MOD(a.TOTAL_TIME,3600)/60),'FM00') || ':' ||
                TO_CHAR(MOD(a.TOTAL_TIME,60),'FM00') as TOTAL_TIME,

                a.ASSIGN_DATE,a.TIME_START,a.TIME_STOP,
                r.SUBMITTED_BY,r.REGISTER_DATE,r.DESCRIPTION 


                FROM table_a a 
                JOIN table_r ON a.REQ_ID = r.REQ_ID 
                JOIN table_e e ON e.emp_id = a.emp_id

                LEFT JOIN my_table@link z ON e.emp_id = z.id

                WHERE a.ASSIGN_DATE > '01-JAN-2013' and a.ASSIGN_DATE < '01-JAN-2015'

                ORDER BY r.RFC_NUMBER;

table_a, table_r and table_e are oracle tables. table my_table is mssql table that is being accessed via link.

so my question is how to join oracle tables with linked mssql table?

Answer 1

From your comments I believe the issue is that SQL Server uses case-sensitive column names by default (more specific information can be found at this link ), while Oracle will only use case-sensitive column names if these are enclosed in double quotes " . So if the column id in your SQL Server table is lowercase, you'll need to use quotes around this column name in Oracle. That is, if you don't put quotes around a column name in Oracle, it assumes uppercase. So z.id will look for a column named ID while z."id" will look for a column named id . Specifically, this line:

LEFT JOIN my_table@link z ON e.emp_id = z.id

should be this:

LEFT JOIN my_table@link z ON e.emp_id = z."id"

Hope this helps.