Question

我有一个主表，其中包含与该表对应的表名和列。

我想编写一个迭代表的所有记录并获取所有数据并将其作为单个结果集返回的过程。

Answer 1

您需要使用Dynamic Query

DECLARE @sql VARCHAR(max)=''

SET @sql = (SELECT @sql + 'select ' + column_name + ' from '
                   + table_name + ' union all '
            FROM   master_table
            FOR xml path(''))

SELECT @sql = LEFT(@sql, Len(@sql) - 9) 
EXEC (@sql)

注意：所有列的数据类型应相同。如果不是这种情况，那么您可能必须明确转换为varchar

SET @sql = (SELECT @sql + 'select cast(' + column_name + ' as varchar(4000)) from '
                        + table_name
                   + ' union all '
            FROM   Master_table
            FOR xml path(''))

Answer 2

假设Master表中列出的所有表具有相同的列和相同的订单和数据类型。然后它将如下：

create table ##a
(
    Value int
)

create table ##b
(
    Value int
)

create table ##c
(
    Value int
)

declare @all table
(
    Value int
)

declare @master table
(
    TableName varchar(10)
)

declare @TableName varchar(10)

insert ##a values (1), (2), (3)
insert ##b values (4), (5), (6)
insert ##c values (7), (8), (9)

insert @master values ('##a'), ('##b'),('##c')

declare looper cursor local static forward_only read_only for 
select TableName from @master
open looper
fetch next from looper into @TableName
while @@fetch_status = 0
begin
    insert @all exec('select Value from ' + @TableName)
    fetch next from looper into @TableName
end
close looper
deallocate looper

select * from @all

drop table ##a
drop table ##b
drop table ##c

如果表格结构不同，请访问Stored procedures and multiple result sets in T-SQL。它会将每个表的内容压缩到一个XML单元中。文章还解释了如何阅读它们。

Answer 3

我假设您在主表中使用了许多具有不同列的表。你应该循环你的主表。试试这样，

   DECLARE @sql NVARCHAR(max) = ''
DECLARE @start INT = 1
    ,@end INT = 0
    ,@tablename VARCHAR(100) = ''
DECLARE @TableList TABLE (
    id INT identity(1, 1)
    ,tablename VARCHAR(128)
    )

INSERT INTO @TableList (tablename)
SELECT DISTINCT table_name
FROM YourMasterTableName
WHERE TABLE_NAME = 'productss'

SET @end = @@ROWCOUNT

WHILE (@start <= @end)
BEGIN
    SET @tablename = (
            SELECT tablename
            FROM @TableList
            WHERE id = @start
            )
    SET @sql = (
            SELECT ',[' + column_name + ']'
            FROM YourMasterTableName M
            WHERE TABLE_NAME = @tablename
            FOR XML path('')
            )
    SET @sql = 'SELECT ' + stuff(@sql, 1, 1, '') + ' FROM ' + @tablename

    EXEC sp_executesql @sql

    SET @start = @start + 1
END

如何编写程序来获取表的所有数据？

3 个答案: