Yes, you can reuse variables. This is how you do it: SELECT @total_sale := s.f1 + s.f2 as total_sale, s.f1 / @total_sale as f1_percent FROM sales s Read more about it here: http://dev.mysql.com/doc/refman/5.0/en/user-variables.html [Note: This behavior is undefined. According to the MySQL docs:] As a general rule, you should never assign a value to a … Read more
Don’t mix ANSI-89 style and ANSI-92 style joins. They have different precedence which can lead to confusing errors, and that is what has happened here. Your query is being interpreted as follows: FROM property p, ( propertygeometry pg JOIN shortlist sl ON sl.PropertyID = p.id AND sl.MemberID = 384216 … ) In the above, the … Read more
Try using different quotes for “y” as the identifier quote character is the backtick (`). Otherwise MySQL “thinks” that you point to a column named “y”. See also MySQL 8 Documentation Please use double-/single quotes for values, strings, etc. Use backticks for column-names only.
SQL is evaluated backwards, from right to left. So the where clause is parsed and evaluate prior to the select clause. Because of this the aliasing of u_name to user_name has not yet occurred.
You can only use column aliases in GROUP BY, ORDER BY, or HAVING clauses. Standard SQL doesn’t allow you to refer to a column alias in a WHERE clause. This restriction is imposed because when the WHERE code is executed, the column value may not yet be determined. Copied from MySQL documentation As pointed in … Read more