我想在一个存储过程中得到这个查询的结果。使用此查询,我想将行数返回table1
到table4
select count(*) from table1
select count(*) from table2
select count(*) from table3
select count(*) from table4
我想在临时表中得到这个结果并选择临时表的所有列。
我想在一个存储过程中得到这个查询的结果。使用此查询,我想将行数返回table1
到table4
select count(*) from table1
select count(*) from table2
select count(*) from table3
select count(*) from table4
我想在临时表中得到这个结果并选择临时表的所有列。
这是一个不太优雅的解决方案:
SELECT 'table1' as table_name, COUNT(*) as record_count from table1
UNION ALL
SELECT 'table2' as table_name, COUNT(*) as record_count from table2
UNION ALL
SELECT 'table3' as table_name, COUNT(*) as record_count from table3
UNION ALL
SELECT 'table4' as table_name, COUNT(*) as record_count from table4
要在单个记录中执行此操作,您可以执行以下操作:
SELECT (SELECT COUNT(*) from table1) table1_rec_count,
(SELECT COUNT(*) from table2) table2_rec_count,
(SELECT COUNT(*) from table3) table3_rec_count,
(SELECT COUNT(*) from table4) table4_rec_count
同样,这不是一个优雅的解决方案。
INSERT INTO #temp
SELECT * FROM
(
select Cnt = count(*) from table1 Union All
select count(*) from table2 Union All
select count(*) from table3 Union All
select count(*) from table4
)X
DROP TABLE #temp
myCommand.CommandType = CommandType.StoredProcedure;
myCommand.Connection = myConnection;
myCommand.CommandText = "MyProc";
try
{
myConnection.Open();
myReader = myCommand.ExecuteReader();
while (myReader.Read())
{
//Write logic to process data for the first result.
}
myReader.NextResult();
while (myReader.Read())
{
//Write logic to process data for the second result.
}
}
catch(Exception ex)
{
// catch exceptions
}
finally
{
myConnection.Close();
}
假设使用 SQL Server,我发现dm_db_partition_stats
这是一种快速获取行数的可靠方法:
SELECT [TableName] = '[' + s.name +'].[' + t.name + ']'
, [RowCount] = SUM(p.row_count)OVER(PARTITION BY t.object_id)
FROM sys.tables t
JOIN sys.schemas s ON s.schema_id = t.schema_id
JOIN sys.dm_db_partition_stats p ON p.object_id = t.object_id
WHERE t.[type] = 'U'
AND p.index_id IN (0,1)
AND t.name IN ('table1','table2','table3','table4') --Just table names here, but it's best practice to also include schemas
ORDER BY s.name, t.name