java如何编写SQL查询以从两个表中获取数据

Question

@Entity
@Table(name = "campaigns")
@SqlResultSetMapping(name = "CampaignResultSet", classes = {
        @ConstructorResult(targetClass = Campaign.class, columns = {
                @ColumnResult(name = "campaign_sno", type = Long.class),
                @ColumnResult(name = "campaign_id", type = String.class),
                @ColumnResult(name = "campaign_title", type = String.class),
                @ColumnResult(name = "campaign_label", type = String.class),
                @ColumnResult(name = "campaign_description", type = String.class),
                @ColumnResult(name = "campaign_type", type = String.class),
                @ColumnResult(name = "email_subject", type = String.class),
                @ColumnResult(name = "from_name", type = String.class),
                @ColumnResult(name = "from_email", type = String.class),
                @ColumnResult(name = "to_name_type", type = String.class),
                @ColumnResult(name = "email_type", type = String.class),
                @ColumnResult(name = "email_status", type = Boolean.class),
                @ColumnResult(name = "api_key", type = String.class),
                @ColumnResult(name = "list_id", type = String.class),
                @ColumnResult(name = "created_by", type = Long.class),
                @ColumnResult(name = "created_date", type = Date.class),
                @ColumnResult(name = "updated_by", type = Long.class),
                @ColumnResult(name = "updated_date", type = Date.class) }) }, entities = {
                        @EntityResult(entityClass = Template.class, fields = {
                                @FieldResult(name = "templateSno", column = "template_sno"),
                                @FieldResult(name = "baseTemplateId", column = "base_template_id"),
                                @FieldResult(name = "templateName", column = "template_name"),
                                @FieldResult(name = "bodyHeader", column = "body_header"),
                                @FieldResult(name = "bodySubject", column = "body_subject"),
                                @FieldResult(name = "bodyContent", column = "body_content"),
                                @FieldResult(name = "bodyFooter", column = "body_footer"),
                                @FieldResult(name = "sourceCode", column = "source_code"),
                                @FieldResult(name = "modifiedCode", column = "modified_code"),
                                @FieldResult(name = "extractedCode", column = "extracted_code"),
                                @FieldResult(name = "createdBy", column = "created_by"),
                                @FieldResult(name = "createdDate", column = "created_date"),
                                @FieldResult(name = "updatedBy", column = "updated_by"),
                                @FieldResult(name = "updatedDate", column = "updated_date") }) })

我的查询是从活动中选择*。 在活动表中，我有一个引用列名为template\u id，它将引用templates表中的template\u sno列。在检索活动时，我还需要模板数据。那么，如何编写查询以获取记录呢

Answer 1

以下查询将帮助您仅在数据相关时显示两个表中的所有字段

选择* 来自c 在c.template\u id=t.template\u id上连接模板t