is.na-methods: Query if the entries in a table are NULL

In greenplum-db/GreenplumR: A Fast, Easy-to-Use Tool for Manipulating Tables in Databases

Query if the entries in a table are NULL

Description

This function is equivalent to an SQL query that checks if the entries in a table are NULL.

Usage

## S4 method for signature 'db.obj'
is.na(x)

Arguments

x	The signature of the method. A db.obj object.

Details

is.na() creates a db.Rquery object where the NULL entries in a db.obj object are TRUE, and other the entries are FALSE.

Value

The return value is a db.Rquery object.

Author(s)

Author: Predictive Analytics Team at Pivotal Inc.

Maintainer: Frank McQuillan, Pivotal Inc. [e-mail]

See Also

lk or lookat Displays the contents of a db.obj object.

Examples

## Not run: 


## set up the database connection
## Assume that .port is port number and .dbname is the database name
cid <- db.connect(port = .port, dbname = .dbname, verbose = FALSE)

## create a temp table from the example data.frame "abalone"
x <- as.db.data.frame(abalone, conn.id = cid, verbose = FALSE)

#Query which entries of x are NULL
is.na(x)

y <- x
y[is.na(y)] <- 3

z <- x
z[is.na(x$height),"height"] <- 23

db.disconnect(cid, verbose = FALSE)

## End(Not run)

greenplum-db/GreenplumR documentation built on Sept. 2, 2023, 8:09 a.m.