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unknown authored
View definition as SELECT ... FROM DUAL WHERE ... has valid syntax, but use of such view in SELECT or SHOW CREATE VIEW syntax causes unexpected syntax error. Server omits FROM DUAL clause when storing view body string in a .frm file for further evaluation. However, syntax of SELECT-witout-FROM query is more restrictive than SELECT FROM DUAL syntax, and doesn't allow the WHERE clause. NOTE: this syntax difference is not documented. View registration procedure has been modified to preserve original structure of view's body. mysql-test/r/view.result: Added test case for bug #35193. mysql-test/t/view.test: Added test case for bug #35193. sql/sql_select.cc: Fixed bug #35193. The st_select_lex::print function always omits FROM DUAL clause, even if original SELECT query has the WHERE clause. The mysql_register_view function uses this function to reconstruct a body of view's AS clause for further evaluation and stores that reconstructed clause in a .frm file. SELECT without FROM syntax is more restrictive than SELECT FROM DUAL syntax: second one allows the WHERE clause, but first one is not. Use of this view in SELECT or SHOW CREATE VIEW queries causes unexpected syntax errors. The st_select_lex::print function has been modified to reconstruct FROM DUAL clause in queries when needed. TODO: Syntax difference is not documented and should be eliminated, however improvement of the SELECT-without-FROM syntax is not trivial and leads to significant modification of grammar file because of additional shift/reduce conflicts.
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