Data Type Precedence
When an operation can return several different values, and these values may have different data types, InterSystems IRIS assigns the return value whichever data type has the highest precedence. For example, a NUMERIC data type can contain all possible INTEGER data type values, but an INTEGER data type cannot contain all possible NUMERIC data type values. Thus NUMERIC has the higher precedence (is more inclusive).
For example, if a CASE statement has a possible result value of data type INTEGER, and a possible result value of data type NUMERIC, the actual result is always of type NUMERIC, regardless of which of these two cases are taken.
The precedence for data types is as follows, from highest (most inclusive) to lowest:
LONGVARBINARY
LONGVARCHAR
VARBINARY
VARCHAR
GUID
TIMESTAMP
DOUBLE
NUMERIC
BIGINT
INTEGER
DATE
TIME
SMALLINT
TINYINT
BIT
