November 20, 2001 at 7:49 am
Do you know how to use SQL to make an 'indirection'. You remember in the C language, how you can treat the contents of a variable as a pointer to another variable location, or in other 4th generation languages (& some OS stuff), you can use a 'handle' to hold an indirect reference to another variable...
I want to do something similar in SQL. I want a column in a table to hold a string that is a column name. I want to create an SQL statement that will use the value of that column name and perform a comparison.
For example, there it a table:
Table: T_Compare_Columns
( col_name char(50) )
Another table:
Table: T_Datastuff
( name_ch char(20),
county_ch char(20),
salary_dc decimal ( 12,2) )
Insert a line into T_Compare_columns:
Insert into T_Compare_columns
values ( 'county_cd' )
Then use that to perform an 'indirect reference' comparison. This statement is pure fiction. I know it will not work in this form:
select *
from T_Datastuff
where T_Compare_column.col_name = T_datastuff.COLUMN_NAME
and t_datastuff.COLUMN_NAME = 'RICHLAND'
Alena B
Alena B
November 20, 2001 at 3:46 pm
I think the only way to do this is via dynamic sql
Cursors never.
DTS - only when needed and never to control.
November 20, 2001 at 7:21 pm
Yes, you can only do this with dynamic sql.
Steve Jones
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November 22, 2001 at 3:13 am
What they mean by Dynamic SQL is that ,
Decide what Ideally your SQL should look like.
I think there is still some haziness over there.
Then decide what is dymanic in that SQL and
what can be passed as parameters to a stored procedure
Thirdly set a varchar variable to that ideal SQL u want.
Then code the stored procedure to use sp_execute sql to fire the query.
Regards,
RB
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