I need to search data in a visualforce with criteria from multiple field.
The field which will be used as Critieria are:
Purpose__c  : Picklist
Condition__c : Picklist
Prod__c : Text
UM__c: Picklist
Container__c: Text

the code below allow me to set criteria for one field. Help me to improve it.

public with sharing class InventorySearchController { 
public list <Articles_Containers__c> inventoryItem {get;set;} 
public string searchstring {get;set;} 
public InventorySearchController( ) { 
} 
public void search(){ 
string searchquery= 'select Name , Prod__c, UM__c, Container__c, Number__c, On_Hand__c,  Pending__c,  Available__c, Purpose__c, Condition__c, Age__c, Comments__c FROM Articles_Containers__c  WHERE Prod__c like \'%'+searchstring+'%\'  AND On_Hand__c >0  AND IsOpened__c = 1  Limit 50000';
     
      inventoryItem= Database.query(searchquery); 

}
public void clear(){ 
inventoryItem.clear(); 
} 
}

// VF
<apex:page Controller="InventorySearchController"  Sidebar="False"> 
<apex:form > 
<apex:inputText value="{!searchstring}" label="Input"/> 
<apex:commandButton value="Search records" action="{!search}"/> 
<apex:commandButton value="Clear records" action="{!clear}"/> 
<apex:pageBlock title="Search Result"> 
<apex:pageblockTable value="{!inventoryItem}" var="a"> 

<apex:column value="{!a.Name}"/> 
<apex:column value="{!a.Prod__c}"/> 
<apex:column value="{!a.UM__c}"/> 
<apex:column value="{!a.Container__c}"/> 
<apex:column value="{!a.Number__c}"/> 
<apex:column value="{!a.On_Hand__c}"/> 
<apex:column value="{!a.Pending__c}"/> 
<apex:column value="{!a.Available__c}"/> 
<apex:column value="{!a.Purpose__c}"/> 
<apex:column value="{!a.Condition__c}"/> 
<apex:column value="{!a.Age__c}"/> 
<apex:column value="{!a.Comments__c}"/> 
</apex:pageBlockTable> 
</apex:pageBlock> 
</apex:form> 
</apex:page>