variable substitution doesn't for table name?

[Yue Guan]

Hi, there

Is variable substitution good for tables? This is what I tried:

set table_name=test_table;
explain select * from ${hiveconf:table_name};

FAILED: Parse Error: line 1:22 cannot recognize input '$' in join source

So I just want to confirm that variable substitution is only good for
column names?

Thank you