class Book {
    String title
    Date releaseDate
    String author
}countBy*
Purpose
Dynamic method that uses the properties of the domain class to query for the count of the number of matching records
Examples
Given the domain class Book:
The following are all possible:
def c = Book.countByTitle("The Shining")
c = Book.countByTitleAndAuthor("The Sum of All Fears", "Tom Clancy")
c = Book.countByReleaseDateBetween(firstDate, new Date())
c = Book.countByReleaseDateGreaterThanEquals(firstDate)
c = Book.countByTitleLike("%Hobbit%")
c = Book.countByTitleNotEqual("Harry Potter")
c = Book.countByReleaseDateIsNull()
c = Book.countByReleaseDateIsNotNull()Description
GORM supports the notion of Dynamic Finders. The countBy* method counts the number of records for the given expression
The following operator names can be used within the respective dynamic methods:
- 
LessThan
- 
LessThanEquals
- 
GreaterThan
- 
GreaterThanEquals
- 
Between
- 
Like
- 
Ilike(i.e. ignorecase like)
- 
IsNotNull
- 
IsNull
- 
Not
- 
Equal
- 
NotEqual
- 
And
- 
Or
These names can be considered keywords, and you will have problems when querying domain classes that have one of these names as a property name. For more information on dynamic finders refer to the user guide.