postgresql - ''More than one row returned by a subquery used as an expression'' postgres error

I am trying to realize a postgres request :

select distinct nom_reg_12 
from region_15,repartition 
where st_intersects(region_15.geom,
                   (select geom 
                   from repartition 
                   where id_espece='Tetrarti'))=true; 

but i get the following error :

More than one row returned by a subquery used as an expression

in the first time I tried this and it work fine :

select distinct nom_reg_12 
from region_15,repartition 
where st_intersects(region_15.geom,repartition.geom)=true;

and then I tried this a part to get the geometry I want :

select geom from repartition where id_espece='Tetrarti'

Answer

you can move your condition outside of the subquery. ST_Intersects works on 1 row (for each geometry) at a time, so if you use a subquery it must also return just one row, and you probably have more than 1 'Tetrarti' row

select distinct nom_reg_12 
from region_15,repartition 
where id_espece='Tetrarti'
and st_intersects(region_15.geom,
                   repartition.geom)=true;