Table chart does not parse custom sql properly

[Marc Balaban]

🪲 If bug

• Operating System and version:
  OSX
• Browser and version:
  Chrome -- Version 59.0.3071.115
• Steps to reproduce (including dashboard link):

1. Create a dashboard
2. create as custom measure
3. custom measure should have "cast([columnname] as float)

• Description of issue:
  It does not render the data properly on table chart.