Error: Conversion failed when converting the varchar value '10.8' to data type in

Question

我收到错误 "Error: Conversion failed when converting the varchar value '10.8' to data type in."。

我正在 Azure 数据仓库中编写此查询。有什么问题我没有做任何转换为 Int。

select 
  cast(
    case
        when [total_amount] is null then 0
        when [total_amount] = '' then 0
        else [total_amount]
    end
    as decimal(10,4)
)
  FROM [dbo].[ABC]

此查询是一个外部 table 查询，它也报告错误 6 行在查询执行的计划步骤 2 中被外部 table [NYCTaxiData] 拒绝：

Location: '/2016/yellow_tripdata_2016-07.csv' Column ordinal: 17, Expected data type: VARCHAR(50) collate SQL_Latin1_General_CP1_CI_AS, Offending value: VendorID,tpep_pickup_datetime,tpep_dropoff_datetime,passenger_count,trip_distance,RatecodeID,store_and_fwd_flag,PULocationID,DOLocationID,payment_type,fare_amount,extra,mta_tax,tip_amount,tolls_amount,improvement_surcharge,total_amount (Tokenization failed), Error: Not enough columns in this line.
    Location: '/2016/yellow_tripdata_2016-10.csv' Column ordinal: 17, Expected data type: VARCHAR(50) collate SQL_Latin1_General_CP1_CI_AS, Offending value: VendorID,tpep_pickup_datetime,tpep_dropoff_datetime,passenger_count,trip_distance,RatecodeID,store_and_fwd_flag,PULocationID,DOLocationID,payment_type,fare_amount,extra,mta_tax,tip_amount,tolls_amount,improvement_surcharge,total_amount (Tokenization failed), Error: Not enough columns in this line.
    Location: '/2016/yellow_tripdata_2016-11.csv' Column ordinal: 17, Expected data type: VARCHAR(50) collate SQL_Latin1_General_CP1_CI_AS, Offending value: VendorID,tpep_pickup_datetime,tpep_dropoff_datetime,passenger_count,trip_distance,RatecodeID,store_and_fwd_flag,PULocationID,DOLocationID,payment_type,fare_amount,extra,mta_tax,tip_amount,tolls_amount,improvement_surcharge,total_amount (Tokenization failed), Error: Not enough columns in this line.
    Location: '/2016/yellow_tripdata_2016-09.csv' Column ordinal: 17, Expected data type: VARCHAR(50) collate SQL_Latin1_General_CP1_CI_AS, Offending value: VendorID,tpep_pickup_datetime,tpep_dropoff_datetime,passenger_count,trip_distance,RatecodeID,store_and_fwd_flag,PULocationID,DOLocationID,payment_type,fare_amount,extra,mta_tax,tip_amount,tolls_amount,improvement_surcharge,total_amount (Tokenization failed), Error: Not enough columns in this line.
    Location: '/2016/yellow_tripdata_2016-08.csv' Column ordinal: 17, Expected data type: VARCHAR(50) collate SQL_Latin1_General_CP1_CI_AS, Offending value: VendorID,tpep_pickup_datetime,tpep_dropoff_datetime,passenger_count,trip_distance,RatecodeID,store_and_fwd_flag,PULocationID,DOLocationID,payment_type,fare_amount,extra,mta_tax,tip_amount,tolls_amount,improvement_surcharge,total_amount (Tokenization failed), Error: Not enough columns in this line.
    Location: '/2016/yellow_tripdata_2016-12.csv' Column ordinal: 17, Expected data type: VARCHAR(50) collate SQL_Latin1_General_CP1_CI_AS, Offending value: VendorID,tpep_pickup_datetime,tpep_dropoff_datetime,passenger_count,trip_distance,RatecodeID,store_and_fwd_flag,PULocationID,DOLocationID,payment_type,fare_amount,extra,mta_tax,tip_amount,tolls_amount,improvement_surcharge,total_amount (Tokenization failed), Error: Not enough columns in this line.

Answer 1

给你：

DECLARE @N VARCHAR(MAX) = '10.8';

SELECT total_amount = CASE
                      WHEN @N IS NULL THEN 0 
                      WHEN @N = '' then 0 
                      ELSE
                      CAST(@N AS DECIMAL(10,4) )  
END

您的原始代码的问题是 CASE 表达式的数据类型是 INT.

这是因为它有两个分支返回一个整数常量 0 和一个返回 varchar 和 int 的分支 higher datatype precedence 而不是 varchar。

所以它首先尝试将字符串 '10.8' 隐式转换为 int 但失败了。

通过上面的重写，varchar 分支现在变为 decimal(10,4)。这比int的优先级更高，CASE表达式的数据类型现在整体变成了decimal(10,4)，没有问题。

结果：

+==============+
| total_amount |
+==============+
|      10,8000 |
+--------------+

Demo.

Error: Conversion failed when converting the varchar value '10.8' to data type in

Error: Conversion failed when converting the varchar value '10.8' to data type in

sql-server

azure-sqldw