Package com.datastax.driver.core.querybuilder

Class Select.Selection

java.lang.Object

com.datastax.driver.core.querybuilder.Select.Builder

com.datastax.driver.core.querybuilder.Select.Selection

Direct Known Subclasses:

Select.SelectionOrAlias

Enclosing class:

Select

public abstract static class Select.Selection
extends Select.Builder

An Selection clause for an in-construction SELECT statement.

Constructor Summary

Constructors

Constructor	Description
Selection()

Method Summary

Modifier and Type	Method	Description
abstract Select.Builder	all()	Selects all columns (i.e.
Select.SelectionOrAlias	avg(Object column)	Creates an avg(x) built-in function call.
Select.SelectionOrAlias	cast(Object column, DataType targetType)	Creates a cast of an expression to a given CQL type.
abstract Select.SelectionOrAlias	column(String name)	Selects the provided column.
Select.SelectionOrAlias	count(Object column)	Creates a count(x) built-in function call.
abstract Select.Builder	countAll()	Selects the count of all returned rows (i.e.
Select.Selection	distinct()	Uses DISTINCT selection.
abstract Select.SelectionOrAlias	fcall(String name, Object... parameters)	Creates a function call.
Select.Selection	json()	Uses JSON selection.
Select.SelectionOrAlias	max(Object column)	Creates a max(x) built-in function call.
Select.SelectionOrAlias	min(Object column)	Creates a min(x) built-in function call.
Select.SelectionOrAlias	path(String... segments)	Selects the provided path.
Select.SelectionOrAlias	raw(String rawString)	Selects the provided raw expression.
Select.SelectionOrAlias	sum(Object column)	Creates a sum(x) built-in function call.
Select.SelectionOrAlias	toJson(String column)	Creates a toJson() function call.
abstract Select.SelectionOrAlias	ttl(String name)	Selects the ttl of provided column.
abstract Select.SelectionOrAlias	writeTime(String name)	Selects the write time of provided column.

Methods inherited from class com.datastax.driver.core.querybuilder.Select.Builder

from, from, from, from

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Selection

public Selection()

Method Detail

distinct

public Select.Selection distinct()

Uses DISTINCT selection.

Overrides:

distinct in class Select.Builder

Returns:

this in-build SELECT statement.

json

public Select.Selection json()

Uses JSON selection.

Cassandra 2.2 introduced JSON support to SELECT statements: the JSON keyword can be used to return each row as a single JSON encoded map.

Overrides:

json in class Select.Builder

Returns:

this in-build SELECT statement.

See Also:

JSON Support for CQL, JSON Support in Cassandra 2.2, Data retrieval using JSON

all

public abstract Select.Builder all()

Selects all columns (i.e. "SELECT * ...")

Returns:

an in-build SELECT statement.

Throws:

IllegalStateException - if some columns had already been selected for this builder.

countAll

public abstract Select.Builder countAll()

Selects the count of all returned rows (i.e. "SELECT count(*) ...").

Returns:

an in-build SELECT statement.

Throws:

IllegalStateException - if some columns had already been selected for this builder.

column

public abstract Select.SelectionOrAlias column(String name)

Selects the provided column.

Parameters:

name - the new column name to add.

Returns:

this in-build SELECT statement

writeTime

public abstract Select.SelectionOrAlias writeTime(String name)

Selects the write time of provided column.

This is a shortcut for fcall("writetime", QueryBuilder.column(name)).

Parameters:

name - the name of the column to select the write time of.

Returns:

this in-build SELECT statement

ttl

public abstract Select.SelectionOrAlias ttl(String name)

Selects the ttl of provided column.

This is a shortcut for fcall("ttl", QueryBuilder.column(name)).

Parameters:

name - the name of the column to select the ttl of.

Returns:

this in-build SELECT statement

fcall

public abstract Select.SelectionOrAlias fcall(String name,
                                              Object... parameters)

Creates a function call.

Please note that the parameters are interpreted as values, and so fcall("textToBlob", "foo") will generate the string "textToBlob('foo')". If you want to generate "textToBlob(foo)", i.e. if the argument must be interpreted as a column name (in a select clause), you will need to use the QueryBuilder.column(java.lang.String) method, and so fcall("textToBlob", QueryBuilder.column(foo).

Parameters:

name - the name of the function.

parameters - the parameters for the function call.

Returns:

this in-build SELECT statement

cast

public Select.SelectionOrAlias cast(Object column,
                                    DataType targetType)

Creates a cast of an expression to a given CQL type.

Parameters:

column - the expression to cast. It can be a complex expression like a function call.

targetType - the target CQL type to cast to. Use static methods such as DataType.text().

Returns:

this in-build SELECT statement.

raw

public Select.SelectionOrAlias raw(String rawString)

Selects the provided raw expression.

The provided string will be appended to the query as-is, without any form of escaping or quoting.

Parameters:

rawString - the raw expression to add.

Returns:

this in-build SELECT statement

path

public Select.SelectionOrAlias path(String... segments)

Selects the provided path.

All given path segments will be concatenated together with dots. If any segment contains an identifier that needs quoting, caller code is expected to call QueryBuilder.quote(String) prior to invoking this method.

This method is currently only useful when accessing individual fields of a user-defined type (UDT), which is only possible since CASSANDRA-7423.

Note that currently nested UDT fields are not supported and will be rejected by the server as a syntax error.

Parameters:

segments - the segments of the path to create.

Returns:

this in-build SELECT statement

See Also:

CASSANDRA-7423

toJson

public Select.SelectionOrAlias toJson(String column)

Creates a toJson() function call. This is a shortcut for fcall("toJson", QueryBuilder.column(name)).

Support for JSON functions has been added in Cassandra 2.2. The toJson() function is similar to SELECT JSON statements, but applies to a single column value instead of the entire row, and produces a JSON-encoded string representing the normal Cassandra column value.

It may only be used in the selection clause of a SELECT statement.

Parameters:

column - the column to retrieve JSON from.

Returns:

the function call.

See Also:

JSON Support for CQL, JSON Support in Cassandra 2.2

count

public Select.SelectionOrAlias count(Object column)

Creates a count(x) built-in function call.

Returns:

the function call.

max

public Select.SelectionOrAlias max(Object column)

Creates a max(x) built-in function call.

Returns:

the function call.

min

public Select.SelectionOrAlias min(Object column)

Creates a min(x) built-in function call.

Returns:

the function call.

sum

public Select.SelectionOrAlias sum(Object column)

Creates a sum(x) built-in function call.

Returns:

the function call.

avg

public Select.SelectionOrAlias avg(Object column)

Creates an avg(x) built-in function call.

Returns:

the function call.