问题描述
我正在努力处理一些 sql,它应该将两个表中的数据连接在一起,但我还需要将 JSON 数组解析为输出表中的行...
以下是我想连接在一起的 2 个表的示例:
订购
订单号 | 交货日期 |
---|---|
1 | 2020-05-18 07:00:00.000 |
2 | 2020-08-31 07:30:00.000 |
和历史:
订单号 | History_Details |
---|---|
1 | [{"FieldName":"OrderStatusType.Description","FieldType":"String","ValueBefore":"Delivered","ValueAfter":"Undelivered","Action":2}] |
1 | [{"FieldName":"VoucherCode","ValueBefore":"","ValueAfter":"64646456","Action":1},{"FieldName":"PricingType .Description","ValueBefore":"Standard","ValueAfter":"discount","Action":2}] |
2 | [{"FieldName":"InitialComment","ValueAfter":"Test Comment","Action":2},{"FieldName":" Appointment.Date","FieldType":"DateTime","ValueBefore":"2020-08-06T07:30:00.000","ValueAfter":"2020-08-31T07:30:00.000","Action":0 }] |
2 | 空 |
(不幸的是,字符串“null”,而不是 NULL - 我们在加入数据时必须处理)
我想要的是这样的输出:
订单号 | 交货日期 | 字段名称 | ValueBefore | ValueAfter |
---|---|---|---|---|
1 | 2020-05-18 07:00:00.000 | OrderStatusType.Description | 已交付 | 未送达 |
1 | 2020-05-18 07:00:00.000 | 优惠券代码 | 64646456 | |
1 | 2020-05-18 07:00:00.000 | 定价类型.描述 | 标准 | 折扣 |
2 | 2020-08-31 07:30:00.000 | 初始评论 | 测试评论 | |
2 | 2020-08-31 07:30:00.000 | 约会.日期 | 2020-08-06T07:30:00.000 | 2020-08-31T07:30:00.000 |
我可以自己做 2 个查询,我只是在努力加入他们......
即这给了我没有 JSON 分解的一切:
SELECT
o.order_number as [Order Number],o.delivery_date as [Delivery Date],oh.history_details as [History]
FROM [dbo].[Order] o
JOIN [dbo].[History] oh on oh.order_number = o.order_number
WHERE oh.history_details != 'null'
虽然我可以做 JSON 映射,如:
DECLARE @json NVARCHAR(MAX)
SET @json='[{"FieldName":"VoucherCode",{"FieldName":"PricingType.Description","Action":2}]';
SELECT *
FROM OPEnjsON(@json)
WITH (
FieldName varchar(200) '$.FieldName',ValueBefore varchar(200) '$.ValueBefore',ValueAfter varchar(200) '$.ValueAfter'
)
我真的在努力弄清楚如何将这两个连接在一起并得到我想要的结果,很多 OPEnjsON 示例就像我上面的示例,它们似乎期望单个列/数据类型.
解决方法
您的问题在这里有点问题,因为您想要的输出与您问题的其余部分相矛盾。同一列中不能有不同的数据类型,因此无法在为每个值保留适当数据类型的同时获得所需的输出。
您的选择是将数据保留为文本字符串,因为它显示在 JSON 中,或者为可以捕获的每种可能的数据类型设置多个列。
如果这只是一个记录更改历史记录的日志表,您不会定期查询,那么您可能只需将值保留为文本字符串即可。
查询
declare @Order table(Order_Number int,Delivery_Date datetime);
insert into @Order values
(1,'2020-05-18 07:00:00.000'),(2,'2020-08-31 07:30:00.000')
;
declare @History table(Order_Number int,History_Details varchar(max));
insert into @History values
(1,'[{"FieldName":"OrderStatusType.Description","FieldType":"String","ValueBefore":"Delivered","ValueAfter":"Undelivered","Action":2}]'),(1,'[{"FieldName":"VoucherCode","ValueBefore":"","ValueAfter":"64646456","Action":1},{"FieldName":"PricingType.Description","ValueBefore":"Standard","ValueAfter":"Discount",'[{"FieldName":"InitialComment","ValueAfter":"Test Comment","Action":2},{"FieldName":"Appointment.Date","FieldType":"DateTime","ValueBefore":"2020-08-06T07:30:00.000","ValueAfter":"2020-08-31T07:30:00.000","Action":0}]'),'null')
;
select o.Order_Number,o.Delivery_Date,j.FieldName,j.ValueBefore,j.ValueAfter,case when j.FieldType = 'String' then j.ValueBefore end as ValueBeforeString,case when j.FieldType = 'DateTime' then try_convert(datetime,127) end as ValueBeforeDateTime,case when j.FieldType = 'String' then j.ValueAfter end as ValueAfterString,127) end as ValueAfterDateTime
from @Order as o
join @History as h
on o.Order_Number = h.Order_Number
outer apply openjson(h.History_Details)
with (FieldName varchar(200) '$.FieldName',FieldType varchar(200) '$.FieldType',ValueBefore varchar(200) '$.ValueBefore',ValueAfter varchar(200) '$.ValueAfter'
) as j
where h.History_Details <> 'null'
order by o.Order_Number,o.Delivery_Date;
输出
订单号 | 交货日期 | 字段名称 | ValueBefore | ValueAfter | ValueBeforeString | ValueBeforeDateTime | ValueAfterString | ValueAfterDateTime |
---|---|---|---|---|---|---|---|---|
1 | 2020-05-18 07:00:00.000 | OrderStatusType.Description | 已交付 | 未送达 | 已交付 | NULL | 未送达 | NULL |
1 | 2020-05-18 07:00:00.000 | 优惠券代码 | 64646456 | NULL | 64646456 | NULL | ||
1 | 2020-05-18 07:00:00.000 | 定价类型.描述 | 标准 | 折扣 | 标准 | NULL | 折扣 | NULL |
2 | 2020-08-31 07:30:00.000 | 初始评论 | 测试评论 | NULL | 测试评论 | NULL | ||
2 | 2020-08-31 07:30:00.000 | 约会.日期 | 2020-08-06T07:30:00.000 | 2020-08-31T07:30:00.000 | NULL | 2020-08-06 07:30:00.000 | NULL | 2020-08-31 07:30:00.000 |
您可以使用 OUTER APPLY
将数据从 History
表推入 OPENJSON
。
我们可以使用 NULLIF
来清除任何表示字符串 'null'
的 JSON
SELECT
o.order_number as [Order Number],o.delivery_date as [Delivery Date],j.ValueAfter
FROM [dbo].[Order] o
JOIN [dbo].[History] oh on oh.order_number = o.order_number
OUTER APPLY OPENJSON(NULLIF(oh.history_details,'null'))
WITH (
FieldName varchar(200) '$.FieldName',ValueBefore varchar(200) '$.ValueBefore',ValueAfter varchar(200) '$.ValueAfter'
) j
正如其他人提到的,同一列中不能有不同的数据类型,因此必须保留 varchar
。