In many dierent application elds the amount and impor- tance of spatio-temporal data (i.e., temporally and/or spa- tially qualied data) is increasing in last years and users need new solutions for their management. In this paper we propose a spatio-temporal query language, called ST4SQL. The proposed language extends the well-known SQL syntax and the T4SQL temporal query language. The proposed query language deals with dierent temporal and spatial se- mantics. These semantics allow one to specify how the sys- tem must manage temporal and spatial dimensions for eval- uating the queries. Moreover, the query language introduces new constructs for grouping data with respect to temporal and spatial dimensions. Both semantics and grouping con- structs take into account and exploit data qualied with granularities.