查询 INFORMATION_SCHEMA.COLUMNS 并得到错误“查询处理器用尽内部资源，无法生成查询计划”答案

【问题标题】：Query INFORMATION_SCHEMA.COLUMNS and get error "query processor ran out of internal resources and could not produce a query plan"查询 INFORMATION_SCHEMA.COLUMNS 并得到错误“查询处理器用尽内部资源，无法生成查询计划”
【发布时间】：2017-06-14 00:57:28
【问题描述】：

我只有 35 个表，但是当我运行下面列出的查询时，我得到了这个错误。查询处理器用尽了内部资源，无法生成查询计划。这是一个罕见的事件，仅适用于极其复杂的查询或引用大量表或分区的查询。请简化查询。如果您认为自己错误地收到了此消息，请联系客户支持服务以获取更多信息。我该如何编写查询以避免此错误？

CREATE TABLE DemoTable
(
    ID INT identity(1,1),
    col nvarchar(20)
)
*/

/*INSERT INTO DemoTable VALUES 
('P000092436'),
('123466'),
('123456'),
('P000092436'),
('13456'),
('P000092436')*/

DECLARE @SearchStr nvarchar(100) = '92436',
        @SQL nvarchar(max) = ''

/*SELECT @SQL = @SQL + 
'UNION 
SELECT '''+ QUOTENAME(t.TABLE_SCHEMA) +'.'+ QUOTENAME(c.TABLE_NAME)  +'.'+QUOTENAME(c.COLUMN_NAME) +''' As ColumnName, 
'''+ @SearchStr +''' As ColumnValue,
(SELECT * FROM '+ QUOTENAME(c.TABLE_NAME) +' WHERE '+ QUOTENAME(c.COLUMN_NAME) +' LIKE ''%'+ @SearchStr +'%'' FOR XML AUTO)
FROM '+ QUOTENAME(c.TABLE_NAME) +' 
WHERE '+ QUOTENAME(c.COLUMN_NAME) +' LIKE ''%'+ @SearchStr +'%''*/
SELECT @SQL = @SQL + 
'UNION 
SELECT '''+ t.TABLE_SCHEMA +'.'+ c.TABLE_NAME  +'.'+c.COLUMN_NAME +''' As ColumnName, 
'''+ @SearchStr +''' As ColumnValue, ' + '''<'' + ' + 'CAST('  + '
(SELECT ' + n.LIST_COLUMN + 'FROM '+ c.TABLE_NAME +' WHERE '+ c.COLUMN_NAME +' LIKE ''%'+ @SearchStr +'%'' FOR XML PATH(''''), TYPE) AS VARCHAR(MAX)) + ''/>''
 FROM '+ c.TABLE_NAME +' 
WHERE '+ c.COLUMN_NAME +' LIKE ''%'+ @SearchStr +'%''
'
--SELECT c.COLUMN_NAME, t.TABLE_NAME, n.LIST_COLUMN
FROM INFORMATION_SCHEMA.COLUMNS c
INNER JOIN INFORMATION_SCHEMA.TABLES t ON c.TABLE_NAME = t.TABLE_NAME
INNER JOIN
(
select
b.TABLE_NAME,
stuff((select ',''"'' + CAST('+ a.COLUMN_NAME  + ' AS VARCHAR(200)) + ''",'''
       from INFORMATION_SCHEMA.COLUMNS a 
       where a.TABLE_NAME = b.TABLE_NAME 
       For XML PATH('')),1,1,'')  LIST_COLUMN
from (select distinct TABLE_NAME  from INFORMATION_SCHEMA.COLUMNS) b
) n ON n.TABLE_NAME = c.TABLE_NAME

WHERE t.TABLE_TYPE = 'BASE TABLE';

SET @SQL = STUFF(@SQL, 1, 7, '')

IF OBJECT_ID('tempdb..#SearchResults') IS NOT NULL
  /*Then it exists*/
DROP TABLE #SearchResults

CREATE TABLE #SearchResults
(
    ColumnName nvarchar(500), 
    ColumnValue nvarchar(100),
    --RowContent XML 
    RowContent nvarchar(max)
)
PRINT @SQL;
INSERT INTO #SearchResults
EXEC(@SQL)

SELECT * 
FROM #SearchResults

【问题讨论】：

标签： qtsql

【解决方案1】：

不清楚您使用此查询的目标是什么，但 UNION 语句非常昂贵。您需要重写查询。

也许您可以使用 BEGIN/END 来逐行填充您的表格评估。

【讨论】：