FROM

Possible structures:

• table representation
• SQL operators
• Array with combination of possible structures.

from: 'table_name table_alias' || :table_name
from: [:table_name, :table_alias]
# => 'FROM table_name table_alias '
from: [:_values, [1, 2], :rgl, [:zgl, :gl]]
# => 'FROM (VALUES(1, 2)) AS rgl (zgl, gl)'
from: [[:table_name, :table_alias], [:_values, [1, 2], :values_name, [*values_column_names]]]
# => 'FROM table_name table_alias, (VALUES(1, 2)) AS values_name (v_c_1, v_c_2)'

I do not like the from syntax, but how it can be made more convenient...?