Adding up (+) variables in expression builder results in concatenation

[qgib]

Author Name: Rombert Stapel (@rjstapel)
Original Redmine Issue: 14083
Affected QGIS version: 2.12.1
Redmine category:expressions

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If I add up two variables using the expression builder, the two values are concatenated, instead of added up. So if A = 2091 and B = 0, I get the result of A+B = "20910" (as if I used the || operator). The other operators (-, /, *) seem to work as they should. If I add up two integers, there is no problem.
I have the latest QGIS on the Mac. Version 2.12.2 is not yet available on the Mac, so I am not sure if the bug is still present there.

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• Schermafbeelding_2016-01-11_om_13.29.24.png (Rombert Stapel)
• Schermafbeelding_2016-01-11_om_13.28.46.png (Rombert Stapel)

[qgib]

Author Name: Giovanni Manghi (@gioman)

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your fields are text, not integers or decimals, I would say that the results is the expected one.

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• status_id was changed from Open to Feedback
• fixed_version_id removed Future Release - High Priority
• priority_id was changed from High to Normal

[qgib]

Author Name: Nyall Dawson (@nyalldawson)

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Variables are always string values. You can convert them to a number using the expression functions to_real or to_int, eg 'to_real(@var1) + to_real(@var2)'

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• status_id was changed from Feedback to Closed
• resolution was changed from to invalid

[qgib]

Author Name: Rombert Stapel (@rjstapel)

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That would not explain why I can multiply, subtract and divide the same numbers without any problem. The variables in question are designated as integers, not string values. In my view this is still a bug.

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• status_id was changed from Closed to Reopened

[qgib]

Author Name: Nathan Woodrow (@NathanW2)

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What are the types of the columns?

[qgib]

Author Name: Nyall Dawson (@nyalldawson)

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Wrapping the variables in to_int/to_real is the correct solution. Multiply/etc have special handling to basically have to_real forced, but that's not possible with + because it's also reused for string concatenation. Otherwise the expression '5' + '2' would incorrectly return 7 instead of 52.

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• status_id was changed from Reopened to Closed