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[英]How to use user-defined function in Entity Framework Core (Oracle)?
[英]how to use the condition field is null in Entity Framework Core (Oracle)
我需要在 linq 中使用條件“field is null”,我嘗試使用“field == null”但它沒有給我帶來記錄。
var query = from p in _context.Product
where p.PRODUCT_IND_CHANGE == null
select new ProductViewModel { Id = p.PRODUCT_ID, name = p.PRODUCT_NAME };
我做了這個小子查詢來理解為什么它不起作用。
SELECT
(SELECT count(1)
FROM PRODUCTS
WHERE PRODUCT_IND_CHANGE != NULL
) AS SYMBOL_OPERATOR1
,(SELECT count(1)
FROM PRODUCTS
WHERE PRODUCT_IND_CHANGE IS NULL
) AS SYMBOL_OPERATOR2
FROM DUAL
有沒有辦法在 linq 中使用“where field is null”或模擬它?
圖書館:
更新 1:
剛剛查看了日志,轉換為pl sql代碼時打印如下
2022-10-06 17:36:53.0309|DEBUG|Microsoft.EntityFrameworkCore.Query|192.168.1.15|Generated query execution expression:
'queryContext => new SingleQueryingEnumerable<ProductViewModel>(
(RelationalQueryContext)queryContext,
RelationalCommandCache.SelectExpression(
Projection Mapping:
Id -> 0
Name -> 1
SELECT s.PRODUCT_ID AS Id, s.PRODUCT_NAME AS Name
FROM PRODUCT AS s
WHERE s.PRODUCT_IND_CHANGE == NULL),
Func<QueryContext, DbDataReader, ResultContext, SingleQueryResultCoordinator, ProductViewModel>,
API.SGA.Products.Data.DbContext,
False,
False,
True
)'|
你試過了嗎
where p.PRODUCT_IND_CHANGE.Equals(null)
在 Linq?
在SQL應該是
WHERE PRODUCT_IND_CHANGE IS NOT NULL
您班級的“PRODUCT_IND_CHANGE”屬性是否可以為空? 就像是
public int? PRODUCT_IND_CHANGE {get; set; }
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