如何使用 select count(*) from @variable？

Question

我创建了一个

cursor 

来查询模式中的所有表，使用

where 

条件获取总记录，然后

insert 

将此结果放入另一个表中

        DECLARE  @TableName VARCHAR(150), @TotalRecords int
        DECLARE CURSOR_TABLENAME CURSOR FOR
        SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE [TABLE_SCHEMA] = 'dbo'
        OPEN CURSOR_TABLENAME
        FETCH NEXT FROM CURSOR_TABLENAME INTO @TableName
        WHILE @@FETCH_STATUS = 0
        BEGIN


    
        SET @TotalRecords = (SELECT COUNT(*) FROM @TableName WHERE TenantId = '')

                INSERT INTO PAGINATION (TOTALRECORDS, TABLENAME, TENANTID) VALUES (TotalRecords, @TableName,'')

        FETCH NEXT FROM CURSOR_TABLENAME INTO @TableName
        END
        CLOSE CURSOR_TABLENAME
        DEALLOCATE CURSOR_TABLENAME

如何在Select中使用@TableName？

Answer 1

这就是我们所说的 XY 问题。您根本不需要

COUNT(*)

，也不需要

CURSOR

。只需从

sys

对象获取所有数据即可。例如，调整 Brent Ozar 在 How to count the number of rows in a table in SQL Server:

中的解决方案

SELECT s.name AS SchemaName,
       t.name AS TableName,
       SUM(p.rows) AS TableRows
FROM sys.schemas s
     JOIN sys.tables t ON s.schema_id = t.schema_id
     INNER JOIN sys.partitions p ON t.object_id = p.object_id
     INNER JOIN sys.indexes i ON p.object_id = i.object_id
                             AND p.index_id = i.index_id
WHERE i.index_id < 2
GROUP BY s.name,
         t.name;