Error "Can't compare {type} and {type} values" in Calculation Editor

Issue

When writing a condition in a calculation, then the calculated field is invalid with an error similar to

Can't compare {type} and {type} values

For example:

Can't compare date and string values

or,

Can't compare datetime and string values

The error will occur with these combinations of data types:

	String	Float	Integer	Boolean	Date/Datetime
String		X	X	X	X
Float	X			X	X
Integer	X			X	X
Boolean	X	X	X		X
Date/Datetime	X	X	X	X

Environment

Tableau Desktop

Resolution

Only compare values of the same type. Depending the calculation this may mean that using a different field or literal value, or converting one of the fields or literal values. The "can't compare example.twbx" workbook in the right-hand pane of this article provides some examples.

[Date Field] = "1/1/2019" could become [Date Field] = #1/1/2019#
[Text Field with Only Number Values] = [Number Field] could become FLOAT([Text Field with Only Number Values] ) = [Number Field]
[Mixed Text Field] = [Number Field] could become [Mixed Text Field] = STR([Number Field])

Cause

Fields and/or literal values must have the same data type to be compared.

Additional Information

Fields with a geographic role also have a data type. The data type, rather than the geographic role, is what must match.

Sets always return Boolean values.

Hashtags are used to define a date literal, such as #1/1/2019#. Quotations are used to define a string literal, such as "text value". Numeric literals do not need special characters, such as 4 or 4.0. Similarly Boolean literals are just the keywords true and false (capitalization does not matter).

Data Types
Type Conversion