Dynamic Search (SOSL)

Dynamic Search refers to the creation of a SOSL string at run time with Apex code. It enables you to create more flexible applications. For example, you can create a search based on input from an end user, or update records with varying field names. To create a dynamic search (SOSL) query at run time, use the search query method. List<List<sObject>> searchResults = search.query(SOSL_search_string);

• SOSL is supported only in apex class and the anonymous block.

• SOSL can not be used in apex trigger.

• If SOSL does not return any records for a specified saelsforce object type, and the result for that sObject type is empty list

The following example a simple SOSL query string.

String soslString='FIND\'Edge*\'IN ALL FIELDS RETURNING Account(id,name,BillingCity),Contact, Lead'; 
List<List<SObject>>searchList=search.query(soslString);
List<Account> accounts = (List<Account>)searchList.get(0);
List<Contact> contacts = (List<Contact>)searchList.get(1);
List<Lead> leads = (List<Lead>)searchList.get(2);

The result lists are always returned in the same order as they were specified in the dynamic SOSL query. From the example above, the results from Account are first index(0), then Contact, then Lead.

Bind Variable in Dynamic SOSL
You can use bind variables in dynamic SOSL string as the following:
This code finds cases which are description contains CASE1 or CASE2 and Account ID is 0019000000NCTyt

String filters ='CASE1 OR CASE2';
String accountID='0019000000NCTyt';

//Account is relationship name of lookup field AccountId on Case
String sosl='FIND:filters IN ALL FIELDS RETURNING Case(id,Subject,Description WHERE Account.Id=:accountID)';
List<List<SObject>> result=search.query(sosl);
System.debug('Result:'+result);

Result:((Case:{Description=Hello, This is CASE2, AccountId=0019000000NCTytAAH, Subject=test CASE2, Id=5009000000pMe00AAC}, Case:{Description=Hello, This is CASE1, AccountId=0019000000NCTytAAH, Subject=Test CASE1, Id=5009000000pMdxBAAS}))