Question

I am trying to use calculations from previous columns in SQL. I tried using variables but had no luck. Here is what i have now:

CREATE VIEW CalculationsTable (id, deltaLat, deltaLon, a, c, d) AS 
  SELECT Resource.id, 
    RADIANS("+lat+"-Resource.lat) AS deltaLat, 
    RADIANS("+lon+"-Resource.lon) AS deltaLon,
    (SIN(deltaLat/2)*SIN(deltaLat/2)) + COS("+lat+") 
       * cos(Resource.lat) * (SIN(deltaLon/2)
       * SIN(deltaLon/2)) AS a, 
    2 * ATAN2(SQRT(a), SQRT(1-a)) AS c, 
    6371 *c AS d 
  FROM Resource AS Resource;

I keep on getting this error:

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column ‘deltaLat’ in ‘field list’

The deltaLat in the error is the deltaLat from this part of the code "(SIN(deltaLat/2)..."

Answer 1

You could try to reformat your query and use a subtable. E.g.

SELECT calcValueA + 3,
  FROM (SELECT A + B calcValueA FROM yourTable);

For your query you have to do it several times.