Clinical Quality Language Specification
2.0.0-ballot - R2 STU 1 (Ballot)

Clinical Quality Language Specification, published by Clinical Decision Support WG. This guide is not an authorized publication; it is the continuous build for version 2.0.0-ballot built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/cql/ and changes regularly. See the Directory of published versions

## V1.1 Change Log

Page standards status: Informative | Maturity Level: N/A

1.1 Change Log

Update 1 Changes:

#954: Changed define clause within the query to let clause to avoid ambiguity in the grammar, as well as potential confusion regarding local vs global defines

#951: Comments moved to the HIDDEN channel

#950: Changed “matches” to “~”

#949: Changed list indexes to be 0-based instead of 1-based

#948: Changed string literals and identifiers to use industry-standard escape sequences

#944: Clarified example in 2.5.8.2

#911: Fixed incorrect reference to MinValue in 9.6.9

#827: Added List`to Code conversion as implicit`

#823: Fixed incorrect definition of the Concept type in 9.1.4

#804: Added Exp operator, inverse of Ln

#803: Renamed Expand to Flatten to better reflect operator semantics

#802: Added examples for properly includes and properly included in

#801: Fixed typographical error

#765: Clarified behavior of value set expansion when code system version is not specified

#763: Added weeks as a supported duration

#762: Fixed an invalid cross reference

#741: Corrected out-of-date diagram of interval operations

#735: Fixed mapping of between operator to ELM

#721: Clarified behavior for forward/circular expressions and function definitions

#719: Clarified behavior of a library when no library header is specified

#718: Clarified documentation of the path attribute for the Property type in ELM

#716: Added ability to use between as an interval constructor for comparison

#713: Corrected description of implicit conversion between structured and class types

#714: Corrected signatures for the Multiply operator in 9.6.11

#715: Clarified that during is a synonym of included in

1.1 Review #1: Changed <> operator to !=

1.1 Review #2: Added support for forward function declarations

1.1 Review #3: Fixed table headers for implicit conversion table

1.1 Review #4: Clarified wording for tuple conversion description

1.1 Review #5: Clarified requirements for indexers in property paths

1.1 Review #6: Clarified semantics for multiplication and division involving quantities

#966: Improved semantics of usingDefinition production rule in grammar

#991: Clarified semantics of the conditional expression

#720: Added top-level constructs for code and concept