SELECT with UNION return String Field truncated at 510 size

[OsquiVilla]

"SELECT with UNION return String Field truncated at 510 size"

I have this error from long time and I couldn´t found a solution.

I use 6 tables and I want to search with SELECT using UNION.

All warks ok if the result data comes from only one table (it means, the 6 selects only return data from only one table)

But if the all 6 selects return data from more than one table, all TEXT fields return truncated strings with exact 510 characters.

Please help me