query.ebnf: rename column to alias

doc/sql/query.ebnf

@@ -15,11 +15,11 @@ DropTable   ::= 'drop table' table ('option' '(' ('timeout' '=' DOUBLE)')')?
 DropRole    ::= 'drop role' role ('option' '(' ('timeout' '=' DOUBLE)')')?
 DropUser    ::= 'drop user' user ('option' '(' ('timeout' '=' DOUBLE)')')?
 Options     ::= 'option' '(' ('vtable_max_rows' '=' UNSIGNED)? (',' 'sql_vdbe_max_steps' '=' UNSIGNED)? ')'
-SELECT      ::= 'SELECT' ((column (',' column)*) ) 'FROM' (table ('AS' name)? | '(' (SELECT | VALUES) ')' ('AS' name)?) ( ('INNER')? 'JOIN' (table ('AS' name)? | ('(' (SELECT | VALUES) ')' ('AS' name)?))  'ON' expression )? ( 'WHERE' expression )? ( 'GROUP BY' expression(',' expression)* )?
+SELECT      ::= 'SELECT' ((alias (',' alias)*) ) 'FROM' (table ('AS' name)? | '(' (SELECT | VALUES) ')' ('AS' name)?) ( ('INNER')? 'JOIN' (table ('AS' name)? | ('(' (SELECT | VALUES) ')' ('AS' name)?))  'ON' expression )? ( 'WHERE' expression )? ( 'GROUP BY' expression(',' expression)* )?
 VALUES      ::= 'VALUES' '(' row (',' row)* ')'
 SUBQUERY    ::= '(' (SELECT | VALUES) ')'
 row         ::= '(' (value (',' value)*) ')'
-column      ::= '*' | (table '.')? name ('AS' name)? |  table '.' '*' | expression ('AS' name)?
+alias      ::= '*' | (table '.')? name ('AS' name)? |  table '.' '*' | expression ('AS' name)?
 expression  ::= column_name
                | 'CAST' '(' expression 'AS' type ')'
                | expression ('IS' ('NOT')? 'NULL')