SQL-Server查询自身结果

Question

我正在尝试确定从我的数据库中删除表的风险。

数据库很大，包含数百个表。

我有一个返回与表关联的外键的查询。所以我可以给它提供我想删除的表名，它会告诉我哪些表依赖于它拥有的列。因此，我还必须删除返回的表。

我的问题来了，因为我需要删除这些表，所以我希望看到任何其他依赖于初始结果的表。

因此，我相信我需要我的查询使用上次运行的结果循环调用自身，直到没有更多唯一结果。

这可能吗？有更简单的方法吗？

编辑:这是查询:

SELECT
      PK.TABLE_NAME AS PrimaryTable,
      FK.TABLE_NAME AS ForeignTable,
      PT.COLUMN_NAME AS PrimaryColumn,
      CU.COLUMN_NAME AS ForeignColumn,
      C.CONSTRAINT_NAME AS ConstraintName
FROM
INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS C
INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS FK ON C.CONSTRAINT_NAME = FK.CONSTRAINT_NAME
INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS PK ON C.UNIQUE_CONSTRAINT_NAME = PK.CONSTRAINT_NAME
INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE CU ON C.CONSTRAINT_NAME = CU.CONSTRAINT_NAME
INNER JOIN (
                  SELECT i1.TABLE_NAME, i2.COLUMN_NAME
                  FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS i1
                  INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE i2 ON i1.CONSTRAINT_NAME = i2.CONSTRAINT_NAME
                  WHERE i1.CONSTRAINT_TYPE = 'PRIMARY KEY'
                  ) PT ON PT.TABLE_NAME = PK.TABLE_NAME
WHERE PK.TABLE_NAME IN
('Table1','Table2')
ORDER BY
1,2,3,4

Answer 1

您可以尝试使用 CTE。我发现在最终 select 语句上编写实际的 where 子句更容易，但如果性能是个问题，我建议您在 relations CTE (在 UNION ALL 之上)

CTE 选择声明

;WITH q AS (
  SELECT
        PK.TABLE_NAME AS PrimaryTable,
        FK.TABLE_NAME AS ForeignTable,
        PT.COLUMN_NAME AS PrimaryColumn,
        CU.COLUMN_NAME AS ForeignColumn,
        C.CONSTRAINT_NAME AS ConstraintName
  FROM
  INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS C
  INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS FK ON C.CONSTRAINT_NAME = FK.CONSTRAINT_NAME
  INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS PK ON C.UNIQUE_CONSTRAINT_NAME = PK.CONSTRAINT_NAME
  INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE CU ON C.CONSTRAINT_NAME = CU.CONSTRAINT_NAME
  INNER JOIN (
                    SELECT i1.TABLE_NAME, i2.COLUMN_NAME
                    FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS i1
                    INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE i2 ON i1.CONSTRAINT_NAME = i2.CONSTRAINT_NAME
                    WHERE i1.CONSTRAINT_TYPE = 'PRIMARY KEY'
                    ) PT ON PT.TABLE_NAME = PK.TABLE_NAME
)
, Relations AS (
  SELECT  PrimaryTable AS Root
          , *
  FROM    q
  UNION ALL
  SELECT  r.Root
          , q.PrimaryTable
          , q.ForeignTable
          , q.PrimaryColumn
          , q.ForeignColumn
          , q.ConstraintName
  FROM    q
          INNER JOIN Relations r ON r.ForeignTable = q.PrimaryTable
)
SELECT  *
FROM    Relations
WHERE   Root IN ('Table1','Table2')
ORDER BY
1,2,3,4