SUBSTRING和CHARINDEX

Question

我需要把 「輸液的進球率：###」 到它自己的領域

我想這個代碼子串（SummaryLine，CHARINDEX（ '晶鑽漾：'，summaryline），+ 14 ）但它不起作用。

, Initial Rate: 40, Goal Rate of Infusion: 0, to goal rate in 8 hours 
, Initial Rate: 30, Goal Rate of Infusion: 0, to goal rate in 8 hours 
, Initial Rate: 10, Goal Rate of Infusion: 10, to goal rate in 8 hours, HOLD FOR N/V 
, Initial Rate: 40, Goal Rate of Infusion: 10, to goal rate in 8 hours 
, Initial Rate: 40, Goal Rate of Infusion: 10, to goal rate in 8 hours 
, Initial Rate: 100, Goal Rate of Infusion: 100, to goal rate in 8 hours 
, Initial Rate: 15, Goal Rate of Infusion: 15, to goal rate in 8 hours 
, Initial Rate: 40, Goal Rate of Infusion: 15, to goal rate in 8 hours 

Answer 1

SELECT 
    SummaryLine, 
    StartIdx, 
    EndIdx, 
    CONVERT(
     int, 
     SUBSTRING(SummaryLine, StartIdx, EndIdx - StartIdx) 
    ) AS InfusionRate 
FROM (
    SELECT 
     SummaryLine, 
     StartIdx, 
     CHARINDEX(',', summaryLine, StartIdx) AS EndIdx 
    FROM (
     SELECT 
      SummaryLine, 
      CHARINDEX('Infusion:', SummaryLine) + 10 AS StartIdx, 
     FROM 
      SourceTable 
    ) 
) 

或者爲單行：

SELECT 
    CONVERT(
     int, 
     SUBSTRING(
      SummaryLine, 
      CHARINDEX('Infusion:', summaryLine) + 10, 
      CHARINDEX(
       ',', 
       SummaryLine, 
       CHARINDEX('Infusion:', summaryLine) + 10 
      ) 
     ) 
    ) 
FROM 
    SourceTable 

SQL不允許你在一個SELECT語句緩存或別名表達的結果，遺憾的是 - 你需要可以使用子查詢（第一個例子）或者重複表達式（第二個例子）。

更新：我做了一些研究，你可以使用CROSS APPLY計算StartIdx只有一次：

SELECT 
    SummaryLine, 
    CONVERT(
     int, 
     SUBSTRING(
      SummaryLine, 
      StartIdx, 
      CHARINDEX(',', summaryLine, StartIdx) - StartIdx 
     ) 
    ) AS InfusionRate 
FROM 
    SourceTable 
    CROSS APPLY (
     SELECT CHARINDEX('Infusion:', summaryLine) + 10 AS StartIdx 
    )