Question

此查询：

SELECT 
   COUNT (a.clientid) AS NumChild
   ,sub.eligtype 
FROM 
    (SELECT 
        CASE 
            WHEN eligibilitytyperecalc IN ('1', '4', '5', '7') THEN 'EstCondition' 
            WHEN eligibilitytyperecalc IN ('2', '6') THEN 'EstDelay' 
            WHEN eligibilitytyperecalc IN ('3', '8') THEN 'AtRisk' 
            ELSE 'Missing' 
        END AS EligType 
    FROM       
        ei_archive..closed_fy13_clientstatus13) AS sub 
INNER JOIN 
   ei_archive..closed_fy13_clientstatus13 a ON sub.eligtype = a.eligibilitytyperecalc
WHERE      
   fy13_finalclientstatus = 14
   AND programid <>40
   AND programid = 01
GROUP BY   
   sub.eligtype

返回错误：

Msg 245，Level 16，State 1，Line 1
转换varchar值时转换失败＆＃39; AtRisk＆＃39;数据类型smallint。

我理解问题（不同的数据类型）但无法确定CONVERT子句的放置位置。我在第一个select语句，CASE语句和GROUP BY中尝试过它。

Answer 1

您尝试将值'AtRisk'转换为无法实现的数值。您可以在子查询中包含数字字段并加入：

SELECT COUNT (a.clientid) AS NumChild
    , sub.eligtype 
FROM 
    (SELECT 
        eligibilitytyperecalc ,   // include key value
        CASE 
            WHEN eligibilitytyperecalc IN ('1', '4', '5', '7') THEN 'EstCondition' 
            WHEN eligibilitytyperecalc IN ('2', '6') THEN 'EstDelay' 
            WHEN eligibilitytyperecalc IN ('3', '8') THEN 'AtRisk' 
            ELSE 'Missing' 
        END AS EligType 
    FROM ei_archive..closed_fy13_clientstatus13) AS sub 
INNER JOIN ei_archive..closed_fy13_clientstatus13 a 
    ON sub.eligibilitytyperecalc = a.eligibilitytyperecalc // join on key field
WHERE  fy13_finalclientstatus = 14
    AND programid <>40
    AND programid = 01
GROUP  BY sub.eligtype

Answer 2

我相信表ei_archive..closed_fy13_clientstatus13的字段eligibilitytyperecalc是一个整数，因此将a.eligibilitytyperecalc转换为char / varchar，因为您要将它与字符串进行比较（ON sub.eligtype = a.eligibilitytyperecalc）。请尝试以下代码

SELECT 
COUNT (a.clientid) AS NumChild
,sub.eligtype 
FROM 
(SELECT 
    CASE 
        WHEN eligibilitytyperecalc IN ('1', '4', '5', '7') THEN 'EstCondition' 
        WHEN eligibilitytyperecalc IN ('2', '6') THEN 'EstDelay' 
        WHEN eligibilitytyperecalc IN ('3', '8') THEN 'AtRisk' 
        ELSE 'Missing' 
    END AS EligType 
FROM       
    ei_archive..closed_fy13_clientstatus13) AS sub 
INNER JOIN 
ei_archive..closed_fy13_clientstatus13 a ON sub.eligtype = cast(a.eligibilitytyperecalc        as char(10))
WHERE      
 fy13_finalclientstatus = 14
AND programid <>40
AND programid = 01
GROUP BY   
sub.eligtype

CASE语句中的CONVERT子句

2 个答案: