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9.19.3. Column Aliasing - AS Declaration
Virtuoso supports the AS operator in the selection list of a SELECT statement. This notation allows declaring a name and optionally a type and precision for a statement's output column.
The syntax is:
as_exp: Scalar_exp AS NAME opt_data_type
For instance, one can write:
SELECT COUNT (*) AS NUMBEROFROWS FROM XX; SELECT COUNT (*) AS NUMBEROFROWS INTEGER (2) FROM XX; SELECT CONCATENATE (COL1, COL2) AS RESULTSTRING VARCHAR (50) FROM XX;
The AS expression tells the client to return specified values in the SQLDescribeCol, SQLColAttribute or equivalent calls. The semantics of statements is not otherwise affected. An AS expression can appear anywhere a scalar expression can but the only place where it has an effect is the selection list of a SELECT statement.
If a data type is given and contains a precision, that precision is returned to the client as the precision of the column in question.