问下各位大佬，我现在写了一个sql的环比同比这2个字段但是得不到值，我是哪块没写对

SELECT city_code 城市,

sum(case when left(week_start,7)='${month}' 

then average_transaction_price

end) 当月商品住宅成交均价,

sum(case when left(week_start,7)='${month}' 

then depolarization_cycle 

end) 当月库存去化周期,

sum(case when left(week_start,4)=left('${month}',4) 

then average_transaction_price * number_of_transactions

end) 当年月商品住宅成交额,

sum(case when left(week_start,7)='${month}'

then average_transaction_price * number_of_transactions

end) 当月商品住宅成交额,

sum(case when left(week_start,4)= CONVERT(varchar(4),DATEADD(year,-1,'${month}'+'-01'), 20)

then average_transaction_price * number_of_transactions 

end) 去年商品住宅成交额,

sum(case when left(week_start,7)= CONVERT(varchar(7),DATEADD(month,-1,'2021-01'+'-01'), 20)

then average_transaction_price * number_of_transactions 

end) 上月商品住宅成交额

FROM [dbo].[t_volume_price_sales_information]

where 1=1

 ${if(city_code=='x00000',""," and city_code = '"+city_code+"'")} 

and enable = 1

and (left(week_start,7) = '2021-07 ') or (left(week_start,7) =CONVERT(varchar(7),DATEADD(month,-1,'2021-07'+'-01'), 20) )

and

(left(week_start,4) = '2021 ') or (left(week_start,4) = CONVERT(varchar(4),DATEADD(year,-1,'2021-07'+'-01'), 20) )

group by city_code