use-queryexpression-class.md

title	description	ms.date	author	ms.author	ms.reviewer	ms.topic	search.audienceType	contributors
Use the QueryExpression class (Microsoft Dataverse) | Microsoft Docs	Use the QueryExpression class to build complex queries for use with the IOrganizationService.QueryBase method or the RetrieveMultipleRequest message.	02/09/2024	divkamath	dikamath	pehecke	article	developer	JimDaly phecke

Use the QueryExpression class

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In Microsoft Dataverse, you can use the xref:Microsoft.Xrm.Sdk.Query.QueryExpression class to build complex queries for use with the xref:Microsoft.Xrm.Sdk.IOrganizationService.xref:Microsoft.Xrm.Sdk.IOrganizationService.RetrieveMultiple* method or the xref:Microsoft.Xrm.Sdk.Messages.RetrieveMultipleRequest message. You can set query parameters to the xref:Microsoft.Xrm.Sdk.Query.QueryExpression by using the xref:Microsoft.Xrm.Sdk.Query.ConditionExpression, xref:Microsoft.Xrm.Sdk.Query.ColumnSet, and xref:Microsoft.Xrm.Sdk.Query.FilterExpression classes.

The xref:Microsoft.Xrm.Sdk.Query.QueryExpression class lets you create complex queries. The xref:Microsoft.Xrm.Sdk.Query.QueryByAttribute class is designed to be a simple way to search for table rows where columns match specified values.

Record count

To find out how many records the query returned, set the xref:Microsoft.Xrm.Sdk.Query.PagingInfo.ReturnTotalRecordCount property to true before executing the query. When you do this, the xref:Microsoft.Xrm.Sdk.EntityCollection.TotalRecordCount is set. Otherwise, this value is -1.

Example

The following sample shows how to use the xref:Microsoft.Xrm.Sdk.Query.QueryExpression class.

//  Query using ConditionExpression and FilterExpression  
ConditionExpression condition1 = new ConditionExpression();  
condition1.AttributeName = "lastname";  
condition1.Operator = ConditionOperator.Equal;  
condition1.Values.Add("Brown");              
  
FilterExpression filter1 = new FilterExpression();  
filter1.Conditions.Add(condition1);  
  
QueryExpression query = new QueryExpression("contact");  
query.ColumnSet.AddColumns("firstname", "lastname");  
query.Criteria.AddFilter(filter1);  
  
EntityCollection result1 = _serviceProxy.RetrieveMultiple(query);  
Console.WriteLine();Console.WriteLine("Query using Query Expression with ConditionExpression and FilterExpression");  
Console.WriteLine("---------------------------------------");  
foreach (var a in result1.Entities)  
{  
    Console.WriteLine("Name: " + a.Attributes["firstname"] + " " + a.Attributes["lastname"]);  
}  
Console.WriteLine("---------------------------------------");  

Use SQL hints in a query

The xref:Microsoft.Xrm.Sdk.Query.QueryExpression class contains a property named xref:Microsoft.Xrm.Sdk.Query.QueryExpression.QueryHints. By setting this property to one of the supported string values shown below, you can provide a hint for generated SQL text that affects the query's execution.

QueryHint value	SQL Query Option and Hint
OptimizeForUnknown	Optimize For Unknown
ForceOrder	Force Order
DisableRowGoal	use hint('Disable_Optimizer_RowGoal')
EnableOptimizerHotfixes	use hint('ENABLE_QUERY_OPTIMIZER_HOTFIXES')
LoopJoin	Loop Join
MergeJoin	Merge Join
HashJoin	Hash Join
NO_PERFORMANCE_SPOOL	NO_PERFORMANCE_SPOOL
MaxRecursion	MAXRECURSION number
ENABLE_HIST_AMENDMENT_FOR_ASC_KEYS	ENABLE_HIST_AMENDMENT_FOR_ASC_KEYS

More information: Hints (Transact-SQL) - Query

See also

Building Queries with QueryExpression
Use the ColumnSet Class
Using the ConditionExpression Class
Using the FilterExpression Class
xref:Microsoft.Xrm.Sdk.Query.QueryExpression

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