我必须使用Entity Framework和Lamda表达式获取titleName匹配“searchText”字符串中至少一个单词的所有标题.当有空格并将结果存储在数组中时,我将分割searchText.我正在编写以下代码但无法获得所需的输出.
var searchTextArray = searchText.Split(' ');
var result = entities.titles.Where(x => searchTextArray.Contains(x.titleName));
假设searchText包含“Loneliness Management”字符串,那么我想获得包含titleName的所有标题的任何单词.
在这种情况下,我应该得到titleNames为的标题
Some loneliness affect all
Loneliness is painful
School Management
Proper management
…
更新1:
上面的查询生成SQL为
SELECT * FROM titles WHERE (LOWER(titleName) IN (N'loneliness', N'management')) AND (LOWER(titleName) IS NOT NULL)
但我想生成像as的查询
SELECT * FROM titles WHERE titleName like N'%loneliness%' or titleName like N'%management%'
我在上面的表达中缺少什么?
更新2
我得到了@ 3dGrabber答案的预期输出但仍然生成的SQL查询比T-SQL中的LIKE运算符有点乱.非常感谢你们.生成的SQL现在就像
SELECT
*
FROM [dbo].[titles] AS [Extent1]
WHERE EXISTS (SELECT
1 AS [C1]
FROM (SELECT
N'loneliness' AS [C1]
FROM ( SELECT 1 AS X ) AS [SingleRowTable1]
UNION ALL
SELECT
N'management' AS [C1]
FROM ( SELECT 1 AS X ) AS [SingleRowTable2]) AS [UnionAll1]
WHERE ( CAST(CHARINDEX([UnionAll1].[C1], LOWER([Extent1].[titleName])) AS int)) > 0
)
最佳答案 不确定EF是否可以转换所有使用的操作,但这是我在Linq-to-Objects中要做的事情:
var searchText = "Loneliness Management";
var searchTerms = searchText.ToLower().Split(' ');
var entities = new []
{
"Some loneliness affect all",
"Loneliness is painful",
"School Management",
"No match here",
"Maybe the next one?",
"Proper management"
};
var titles = entities.Select(t => t.ToLower());
var result = titles.Where(t => searchTerms.Any(s => t.Contains(s)));
如果您需要不区分大小写的搜索,请确保EF支持它,或者首先将数据小写放入DB中.否则你可能会遇到性能问题.