sql - 用于查找与一组属性匹配的行的 SQL 查询

Question

我有以下简化架构:

CREATE TABLE [file]
( 
    id UNIQUEIDENTIFIER NOT NULL, 
    uri NVARCHAR(MAX) NOT NULL, 
    CONSTRAINT PK_file PRIMARY KEY (id ASC) ON [PRIMARY] 
)

CREATE TABLE [property]
( 
    id UNIQUEIDENTIFIER NOT NULL, 
    name NVARCHAR(MAX) NOT NULL, 
    CONSTRAINT PK_property PRIMARY KEY (id ASC) ON [PRIMARY] 
)

CREATE TABLE [metadata]
( 
    fileid UNIQUEIDENTIFIER NOT NULL,
    propertyid UNIQUEIDENTIFIER NOT NULL,
    value NVARCHAR(MAX) NOT NULL, 
    CONSTRAINT PK_metadata PRIMARY KEY (fileid, propertyid ASC) ON [PRIMARY] 
)

其中 [fileid] FK 到 [file].[id] 和 [propertyid] FK 到 [property]。 [id]。假设[properyid]是CLUSTERED并且[value]是NON-CLUSTERED。

我想选择与一组特定元数据匹配的所有文件；例如，每个具有 size = 1 Kb 和 extension = 'txt' 属性值对的文件。

我提出的查询(例如指定了三个属性的查询)是这样的:

SELECT [uri] FROM [file] WHERE [id] IN (
    SELECT a.[fileid] FROM (
        SELECT COUNT(*) [count], [fileid] FROM [metadata]
        WHERE ([propertyid] = '597ddddf-afd2-414f-9774-36f067038064' AND 
                [value] = N'moo') OR
              ([propertyid] = 'd83d12de-e4bc-4d18-be12-743504df3318' AND 
                [value] = N'foo') OR
              ([propertyid] = 'c00c3966-5034-4818-8567-abd660f37f15' AND 
                [value] = N'boo')
        GROUP BY [fileid]
    ) a
    WHERE a.[count] = 3
)

我还能做得更好吗？

Answer 1

;WITH propertylist AS (
  SELECT propertyid = '597ddddf-afd2-414f-9774-36f067038064', value = N'moo' UNION ALL
  SELECT propertyid = 'd83d12de-e4bc-4d18-be12-743504df3318', value = N'foo' UNION ALL
  SELECT propertyid = 'c00c3966-5034-4818-8567-abd660f37f15', value = N'boo'
)
SELECT uri
FROM file
WHERE id IN (
  SELECT m.fileid
  FROM metadata m
    INNER JOIN propertylist p ON m.propertyid = p.propertyid AND m.value = p.value
  GROUP BY m.fileid
  HAVING COUNT(*) = (SELECT COUNT(*) FROM propertylist)
)