union combines two sets a single set. The simplest syntax is
X union Y
where X and Y are sub-expressions giving sets. For example, in a lab where the tests requested for a patient are put as comma-separated values in the two distinct attributes TestsRequested and TestsOrdered, we could get the complete set of tests ordered for a patient using this expression:
TestsRequested as set union TestsOrdered as set
union also combines two sets of attributes into a single set. The syntax is
{ names } in range [lower, upper] union { names } in range [lower, upper]
where:
names are comma separated lists of attribute names or group attribute names
lower and upper are constants or numbers defining the ranges.
For example, suppose you want a comment to contain the names from two sets of allergens
{milk, cod, peanut} in range [15.0,50)
and
{wheat, soya} in range [50,1000]
You can define a calculated value attribute HighAllergens as
{milk, cod, peanut} in range [15.0,50) union {wheat, soya} in range [50,1000]
and the case would then appear as:
age 6 sex F milk 0.0 peanut 43.5 cod 12.1 soya 64.6 wheat 25.3 HighAllergens soya (64.6) and peanut (43.5)
A comment could now be created that used the expression HighAllergens to list those allergens.
Note the following:
- As with all lists of attributes, the attribute names whose values are highest are listed first,
- If more than one attribute value is within the range, the attribute names and values are separated by commas, with the word “and” separating the last two.
See also: for