As disclosed herein a method, executed by a computer, for avoiding double counting in the presence of many-to-many relationships in database data includes receiving a report definition from a data management system, detecting a bridge table defining many-to-many relationships between at least two datasets, generating a query plan with layered sub-queries, and executing the query plan including the layered sub-queries to provide query results corresponding to the report definition. A query plan with layered sub-queries may include instructions to join, partition, normalize, group, and summarize tabular data. Additionally, a conditional selection operation may be used to detect and eliminate duplicated data from a field specified in the report definition. The resulting query plan may be executed as a single query language. A computer program product and an apparatus corresponding to the described method are also disclosed herein.