Package com.orientechnologies.orient.core.sql.functions.misc

Class OSQLFunctionCoalesce

java.lang.Object

com.orientechnologies.orient.core.sql.functions.OSQLFunctionAbstract

com.orientechnologies.orient.core.sql.functions.misc.OSQLFunctionCoalesce

All Implemented Interfaces:

OSQLFunction

public class OSQLFunctionCoalesce
extends OSQLFunctionAbstract

Returns the first field/value not null parameter. if no field/value is not null, returns null.

Syntax:

 coalesce(<field|value>[,<field|value>]*)
 

Examples:

 SELECT coalesce('a', 'b') FROM ...
  -> 'a'

 SELECT coalesce(null, 'b') FROM ...
  -> 'b'

 SELECT coalesce(null, null, 'c') FROM ...
  -> 'c'

 SELECT coalesce(null, null) FROM ...
  -> null

 

Author:

Claudio Tesoriero

Field Summary

Fields

Modifier and Type	Field	Description
static final String	NAME

Fields inherited from class com.orientechnologies.orient.core.sql.functions.OSQLFunctionAbstract

maxParams, minParams, name

Constructor Summary

Constructors

Constructor	Description
OSQLFunctionCoalesce()

Method Summary

Modifier and Type	Method	Description
Object	execute(Object iThis, OIdentifiable iCurrentRecord, Object iCurrentResult, Object[] iParams, OCommandContext iContext)	Process a record.
String	getSyntax()	Returns a convenient SQL String representation of the function.

Methods inherited from class com.orientechnologies.orient.core.sql.functions.OSQLFunctionAbstract

aggregateResults, config, filterResult, getDatabase, getDistributedStorageId, getMaxParams, getMinParams, getName, getResult, getSingleItem, getSingleProperty, mergeDistributedResult, returnDistributedResult, setResult, shouldMergeDistributedResult, toString

Methods inherited from class java.lang.Object

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

Field Details

NAME

public static final String NAME

See Also:

• Constant Field Values

Constructor Details

OSQLFunctionCoalesce

public OSQLFunctionCoalesce()

Method Details

execute

public Object execute(Object iThis,
 OIdentifiable iCurrentRecord,
 Object iCurrentResult,
 Object[] iParams,
 OCommandContext iContext)

Description copied from interface: OSQLFunction

Process a record.

iCurrentRecord - : current record

iCurrentResult - TODO

iParams - : function parameters, number is ensured to be within minParams and maxParams.

iContext - : object calling this function

Returns:

function result, can be null. Special cases : can be null if function aggregate results, can be null if function filter results : this mean result is excluded

getSyntax

public String getSyntax()

Description copied from interface: OSQLFunction

Returns a convenient SQL String representation of the function.

Example :

  myFunction( param1, param2, [optionalParam3])
 

This text will be used in exception messages.

Returns:

String , never null.