如果表中存在列名，如何从sql server数据库中获取所有表并将表数据保存在临时表中

Question

I am trying to write a windows service, which will send automatic emails. all the tables which require email sending have common columns 'templateid' and 'emailstatus'. I want to iterate through all the tables and get the tables which has column name 'templateid'. Now that i have the list of tables with column name 'templateid' get the data from each table whose email status is 'false' and save it in a temporary table. if 'table1' has 4 rows of data, the temporary table should have 4 rows. after iterating through the next table the row collection should be added to the same temporary table.

IF (SELECT object_id('TempDB..#TEMPTABLE')) IS NOT NULL
BEGIN
    DROP TABLE #TEMPTABLE
END
CREATE TABLE #TEMPTABLE(
[ID] INTEGER IDENTITY(1,1) NOT NULL,
[TABLE_NAME] VARCHAR(1000)
)
INSERT INTO #TEMPTABLE(TABLE_NAME)
SELECT TABLE_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE COLUMN_NAME = 'TEMPLATEID'
SELECT * FROM #TEMPTABLE
DECLARE @ROWCOUNT INT
SET @ROWCOUNT = (SELECT COUNT(ID) FROM #TEMPTABLE) 
DECLARE @I INT
SET @I=1
WHILE(@I<=@ROWCOUNT)
BEGIN
    DECLARE @TABLENAME VARCHAR(500)
        SELECT @TABLENAME=TABLE_NAME FROM #TEMPTABLE WHERE ID=@I
        EXEC('SELECT * FROM '+@TABLENAME)
    SET @I=@I+1
END

i found the above query which is giving me all the tables. after that i am clueless how to proceed further as i am not good with sql server.

Answer 1

Not sure you are still looking for an answer but the following code will give you a temporary table with just the tables that have a column named 'templateid'. From here you would need a cursor as Tanner suggested to loop through each table and then insert records from each table (into your final target table) where email status = 'false'.

Here is the code that gets you the temp tables with columns named 'templateid' along with a sample for your cursor:

declare @max_tables int
declare @max_columns int
declare @sql nvarchar(400)
declare @x int
declare @y int
declare @table varchar(50)
declare @columns varchar(800)
declare @tablename varchar(100)

create table #c ([Table] varchar(50),[Columns] varchar(800))

select ROW_NUMBER() OVER(ORDER BY name) AS Row, name 
into #table_list
from sys.objects 
where type_desc = 'USER_TABLE' 
order by name

set @max_tables = (select count(*) from sys.objects where type_desc = 'USER_TABLE')
set @y = 0

while @y < @max_tables
    begin
        set @y = @y + 1
        set @table = (select name from #table_list where row = @y)

        create table #t (c int)

        set @sql = 'select count(*) as c from Information_schema.Columns where table_name = ''' + @table + ''''
        insert into #t exec sp_executesql @sql

        set @max_columns = (select top 1 c from #t)

        DROP TABLE #t

        set @x = 0
        set @columns = ''

        while @x < @max_columns 
            begin
                set @x = @x + 1
                set @columns = @columns + (select column_name from Information_schema.Columns where table_name = @table and ordinal_position = @x)
                if @x < @max_columns set @columns = @columns + ', '
            end

        insert into #c select @table,@columns

    end

select * into #tables from #c c
where c.Columns like '%templateid%'

declare my_cursor cursor for
select table from #t

open my_cursor
fetch next from my_cursor into @tablename

while @@fetch_status = 0
begin

     --do something here to retrieve your data from each table and 
     --insert into target table

end

close my_cursor
deallocate my_cursor


DROP TABLE #c,#tables,#table_List