Question

我有搜索字段，允许用户输入以空格分隔的字样。
我需要在数据库中多个表的 5列中搜索每个单词。
我想创建一个数据库函数，可以从我的 C＃Web服务（实体框架）调用。

目前，我用这个：

CREATE FUNCTION [dbo].[SEARCH_SINGLE] (
    @langId INT = 4,
    @searchString VARCHAR(MAX) = NULL
)
RETURNS TABLE
AS
RETURN
    WITH words AS (
        SELECT * FROM [dbo].splitstring(@searchString, ' ')
    )
    SELECT DISTINCT
        ...
    FROM
        ...
    WHERE
        ...
        AND (
            EXISTS(SELECT t2.Name FROM words t2 WHERE a.[FIRSTNAME] like '%'+t2.Name+'%')
            OR EXISTS(SELECT t2.Name FROM words t2 WHERE a.[LASTNAME] like '%'+t2.Name+'%')
            OR EXISTS(SELECT t2.Name FROM words t2 WHERE c.[CITY] like '%'+t2.Name+'%')
            OR EXISTS(SELECT t2.Name FROM words t2 WHERE j.[PROMO_YEAR] like '%'+t2.Name+'%')
            OR EXISTS(SELECT t2.Name FROM words t2 WHERE e.[EMPLOYOR] like '%'+t2.Name+'%')
        )

它有效，但它会返回与输入的单词匹配的所有记录。我需要返回与至少一列中的所有字词匹配的记录。

例如，如果我们只考虑firstname和lastname：

“John”应该返回“John Doe”，“John Bieber”，“John Daney”等。
“John D％”应该返回“John Doe”和“John Daney”
“John Doe”应仅返回“John Doe”。

实际上，对于像“John Doe McDonald”这样的搜索，我需要像这样模拟一个WHERE：

WHERE 
    (
        a.[FIRSTNAME] like '%John%'
        OR a.[LASTNAME] like '%John%'
        OR c.[CITY] like '%John%'
        OR j.[PROMO_YEAR] like '%John%'
        OR e.[EMPLOYOR] like '%John%'
    ) 
    AND (
        a.[FIRSTNAME] like '%Doe%'
        OR a.[LASTNAME] like '%Doe%'
        OR c.[CITY] like '%Doe%'
        OR j.[PROMO_YEAR] like '%Doe%'
        OR e.[EMPLOYOR] like '%Doe%'
    )
    AND (
        a.[FIRSTNAME] like '%McDonald%'
        OR a.[LASTNAME] like '%McDonald%'
        OR c.[CITY] like '%McDonald%'
        OR j.[PROMO_YEAR] like '%McDonald%'
        OR e.[EMPLOYOR] like '%McDonald%'
    )

理想情况下，如果在整个数据库的5列中找不到单词，只需忽略（“John Doe sjdhf67df”应返回“John Doe”......）。

我试图动态构建查询但是我在返回结果时遇到了一些问题，因为我们无法在函数中使用EXEC ...

我们不暂时考虑全文搜索！

如何我可以修改我的功能以获得预期的结果？

Answer 1

我终于回到了以下解决方案：

CREATE FUNCTION [dbo].[SEARCH_SINGLE] (
    @langId INT = 4,
    @searchString VARCHAR(MAX) = NULL
)
RETURNS TABLE
AS
RETURN
    WITH
words AS (
    SELECT * FROM [dbo].splitstring(@searchString, ' ')
),
results AS (
    SELECT DISTINCT
        a.[ID] as Id,
        a.[LASTNAME] as LastName,
        a.[FIRSTNAME] as FirstName,
        d.[COUNTRY_LABEL] as CountryLabel,
        c.[CITY] as City,
        j.[PROMO_YEAR] as PromoYear,
        CASE WHEN EXISTS(SELECT t2.Name FROM words t2 WHERE a.[FIRSTNAME] like '%'+t2.Name+'%') THEN 1 ELSE 0 END +
        CASE WHEN EXISTS(SELECT t2.Name FROM words t2 WHERE a.[LASTNAME] like '%'+t2.Name+'%') THEN 1 ELSE 0 END +
        CASE WHEN EXISTS(SELECT t2.Name FROM words t2 WHERE c.[CITY] like '%'+t2.Name+'%') THEN 1 ELSE 0 END +
        CASE WHEN EXISTS(SELECT t2.Name FROM words t2 WHERE j.[PROMO_YEAR] like '%'+t2.Name+'%') THEN 1 ELSE 0 END +
        CASE WHEN EXISTS(SELECT t2.Name FROM words t2 WHERE e.[EMPLOYOR] like '%'+t2.Name+'%') THEN 1 ELSE 0 END as Nb
    FROM
        ...
    WHERE
        ...
)
SELECT 
    Id,
    LastName,
    FirstName,
    CountryLabel,
    City,
    PromoYear,
FROM
    results
WHERE
    Nb = (SELECT MAX(Nb) FROM results)
    AND Nb <> 0

我在每列上搜索每个单词。
我给每条记录一个“得分”。
我只返回得分最高的记录。

它似乎涵盖了我的所有要求。

使用LIKE运算符搜索多个列的功能

1 个答案: