sql - PostgreSQL 错误 : "failed to find conversion function from unknown to text"

Question

我有以下 postgresql 查询:

   with A as 
   (
          select '201405MASE04' as TestID, Count(*) TotQ, Count(distinct Case When SE1 = '' then NULL else SE1 end) TotSE, 
                 case when Count(*)=0 then 7 else Count(distinct RC) end TotRC
          from eivTestItems TI, eivTests T 
          where TI.Test_ID = T.Test_ID 
                 and T.Test_Type_ID = 1
                 and T.Test_ID=  '201405MASE04'
                 and TI.Omit <> 1
   ), 
   B as 
   (
          select '201405MASE04' as TestID, Count(*) TotQ
          from eivTestItems TI, eivTests T 
          where TI.Test_ID = T.Test_ID 
                 and T.Test_Type_ID = 1
                 and T.Test_ID=  '201405MASE04'
                 and TI.Omit = 1
   ),
   C as
   (
          select '201405MASE04' as TestID, Count(*) TotQ
          from eivTestItems TI, eivTests T 
          where TI.Test_ID = T.Test_ID 
                 and T.Test_Type_ID = 1
                 and T.Test_ID=  '201405MASE04'
                 and TI.Question_Type_ID='2'
   )

   Select A.TestID, A.TotQ + coalesce(B.TotQ,0) - coalesce(C.TotQ,0) as TotQ, A.TotSE, A.TotRC
   From A
   left outer Join B on A.TestID = B.TestID
   left outer Join C on A.TestID = C.TestID

当我尝试运行此查询时，它向我抛出以下错误:

ERROR:  failed to find conversion function from unknown to text

********** Error **********

ERROR: failed to find conversion function from unknown to text
SQL state: XX000

我如何找出此处出现转换错误的位置？

Answer 1

看起来 postgres 不喜欢你的常量“201405MASE04”。

SQL Fiddle Demo 会产生与您相同的错误。

SQL Fiddle Demo 显示强制转换数据类型可解决问题。

试试这个。我把它定义为文本

with A as 
   (
          select cast('201405MASE04' as text) as TestID, Count(*) TotQ, Count(distinct Case When SE1 = '' then NULL else SE1 end) TotSE, 
                 case when Count(*)=0 then 7 else Count(distinct RC) end TotRC
          from eivTestItems TI, eivTests T 
          where TI.Test_ID = T.Test_ID 
                 and T.Test_Type_ID = 1
                 and T.Test_ID=  '201405MASE04'
                 and TI.Omit <> 1
   ), 
   B as 
   (
          select cast('201405MASE04' as text) as TestID, Count(*) TotQ
          from eivTestItems TI, eivTests T 
          where TI.Test_ID = T.Test_ID 
                 and T.Test_Type_ID = 1
                 and T.Test_ID=  '201405MASE04'
                 and TI.Omit = 1
   ),
   C as
   (
          select cast('201405MASE04' as text) as TestID, Count(*) TotQ
          from eivTestItems TI, eivTests T 
          where TI.Test_ID = T.Test_ID 
                 and T.Test_Type_ID = 1
                 and T.Test_ID=  '201405MASE04'
                 and TI.Question_Type_ID='2'
   )

   Select A.TestID, A.TotQ + coalesce(B.TotQ,0) - coalesce(C.TotQ,0) as TotQ, A.TotSE, A.TotRC
   From A
   left outer Join B on A.TestID = B.TestID
   left outer Join C on A.TestID = C.TestID