我正在执行etl任务，将查询从一种sql方言转换为另一种sql方言。旧数据库使用t-sql，新数据库使用hiveql。

SELECT CAST(CONCAT(FMH.FLUIDMODELID,'_',RESERVOIR,'_',PRESSUREPSIA) AS NVARCHAR(255)) AS FACT_RRFP_INJ_PRESS_R_PHK
, FMH.FluidModelID ,FMH.FluidModelName ,[AnalysisDate] 
    FROM dbo.LZ_RRFP_FluidModelInj fmi 
    LEFT JOIN DBO.LZ_RRFP_FluidModelHeader fmh ON fmi.FluidModelIDFK = fmh.FluidModelID
    LEFT JOIN LZ_RRFP_FluidModelAss fma on fma.InjectionFluidModelIDFK = fmi.FluidModelIDFK
WHERE FMA.RESERVOIR  IN (SELECT RESERVOIR_CD FROM ATT_RESERVOIR)

错误是：

org.apache.spark.sql.catalyst.parser.ParseException: 
DataType nvarchar(255) is not supported.

如何转换nvarchar？