<apex:column>タグ内のヘッダ表示

<apex:page standardController="Contact" recordSetVar="contacts" sidebar="false">
    <!-- https://developer.salesforce.com/forums?id=906F0000000A49NIAS -->

    <apex:form>
        <apex:pageBlock>
            <apex:pageBlockSection>
                <apex:pageBlockSectionItem>
                    <apex:outputLabel for="listView">View</apex:outputLabel>
                    <apex:selectList value="{!filterId}" size="1" multiselect="false">
                        <apex:actionSupport event="onchange" rerender="contactTable"/>
                        <apex:selectOptions value="{!listViewOptions}"/>
                    </apex:selectList>
                </apex:pageBlockSectionItem>
            </apex:pageBlockSection>
        </apex:pageBlock>
    </apex:form>

    <apex:dataTable id="contactTable" value="{!contacts}" var="contact" cellpadding="5">
        <apex:column value="{!contact.AccountId}">
            <apex:facet name="header">
                取引先
            </apex:facet>
        </apex:column>
        <apex:column>
            <apex:facet name="header">
                氏名<br/>
                誕生日
            </apex:facet>
            {!contact.FirstName} {!contact.LastName}<br/>
            誕生日：{!contact.Birthdate}
        </apex:column>
        <apex:column value="{!contact.Title}">
            <apex:facet name="header">
                役職
            </apex:facet>
        </apex:column>
    </apex:dataTable>
</apex:page>