- select x, s from t: Execute the query using PQexec.
- PQntuples(res): The number of rows (tuples) returned.
- PQnfields(res): The number of
columns in the result.
- PQgetisnull(res, r, c): Is column c
of row r NULL? Should always check for NULL before obtaining
column value if there is any chance that the result could be NULL.
- PQgetvalue(res, r, c): Get the value of column c
of row r, as text.