As Enrico mentioned, the rule logic is stored as XML in a rule class, so you can't query the logic directly via SQL.

You can find the names of all rule classes using SQL:
SELECT ID FROM %Dictionary.ClassDefinition where Super='Ens.Rule.Definition'

To then view the rule logic you would need to open a class and view the "RuleDefinition" XData block:

Class ORU.RouterRoutingRule Extends Ens.Rule.Definition
{

Parameter RuleAssistClass = "EnsLib.HL7.MsgRouter.RuleAssist";

XData RuleDefinition [ XMLNamespace = "http://www.intersystems.com/rule" ]
{
<ruleDefinition alias="" context="EnsLib.HL7.MsgRouter.RoutingEngine" production="ADTPKG.FoundationProduction">
<ruleSet name="" effectiveBegin="" effectiveEnd="">
<rule name="">
<when condition="1" comment="">
<send transform="Demo.ORUTransformation" target="ORU.Out"></send>
<send transform="Demo.ORUTransformation" target="ORU.Two"></send>
</when>
</rule>
</ruleSet>
</ruleDefinition>
}

}

Just to clarify a bit:

Are you talking about, for example, HL7 routing rules that are used with the standard business process EnsLib.HL7.MsgRouter.RoutingEngine?

What information do you want to retrieve for the rules?