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UNION SELECT NULL,NULL,NULL-- etc. If the number of nulls does not match the number of columns, the database returns an error, such as: All Use of an unqualified * with other items in the select list may produce a parse error. ... select NULL, email.*, NULL, NULL from email ... the tables...
https://www.docdroid.net/file/download/y6aFEhT/1589610482388-pdf.pdf