Create Table using Schema of SQL Query - sql

I need to create table from the return schema of sql query. Here, sql query has multiple joins.
Example - In below scenario, create table schema for column 'r' & 't'.
select a.x as r b.y as t
from a
JOIN b
ON a.m = b.m
I can not use 'select into statement' because I get an input sql select statement and need to copy the output of that query to destination table at runtime.

If I'm reading your problem correctly, you're getting SQL from an external source and you want to run that into a table (maybe with data, maybe without). This should do:
use tempdb;
declare #userSuppliedSQL nvarchar(max) = N'select top 10 * from Util.dbo.Numbers';
declare #sql nvarchar(max);
set #sql = concat('
with cte as (
', #userSuppliedSQL, '
)
select *
into dbo.temptable
from cte
where 9=0 --delete this line if you actually want data
;');
print #sql
exec sp_executesql #sql;
select * from dbo.temptable;
This assumes that the supplied query is legal for use as the body of a common table expression (e.g. all columns are named and unique). Note that you can't select into a temp table (i.e. #temp) because the temp table only exists for the duration of the sp_executesql call.
Also, for the love of all that is holy, please understand that by running arbitrary SQL that a user passes in, that you're opening yourself up to SQL injection.

I know you said you cannot select into, but can you select into with 0=1 to create an empty table structure and then insert after that?
select a.x as r b.y as t
into TABLE
from a
JOIN b
ON a.m = b.m
where 0 = 1

Use the into clause here. Like
Select col1, col2, col3
into newtable
from old table;
select a.x as r b.y as t
into c
from a
JOIN b ON a.m = b.m

Related

Short-circuiting tables

I'm upgrading several identical copies of a database which may already be upgraded partially, and for some reason bool values were stored in an nvarchar(5).
So in the below, (which exists inside an INSERT > SELECT block), I need to check if the column ShowCol exists, fill it with 0 if it does not, or fill it with the result of evaluating the string bool if it does:
CASE
WHEN COL_LENGTH('dbo.TableName', 'ShowCol') IS NULL THEN 0
ELSE IIF(LOWER(ShowCol) = 'false', 0, 1)
END
...but I'm getting an error "Invalid column name 'ShowCol'". I can't seem to short-circuit this, can you help?
Its worth noting that the column if it does exist contains a mix of "false", "False" and "FALSE", so that's the point of the LOWER(). (The True column also occasional trailing spaces to contend with, which is why I'm just dealing with False and everything else is true.)
I suspect that its because of this wrap in LOWER() which is causing the server to always evaluate the expression.
You can’t short circuit the existence of a column (and it has nothing to do with LOWER(); if you remove it, nothing will change).
You’ll need dynamic SQL, e.g.:
DECLARE #sql nvarchar(max) = N'UPDATE trg SET
trg.col1 = src.col1,
trg.col2 = src.col2';
IF COL_LENGTH('dbo.TableName', 'ShowCol') > 0
BEGIN
SET #sql += N', trg.ShowCol = IIF(LOWER(src.ShowCol) = ''false'', 0, 1)';
END
SET #sql += N' ...
FROM dbo.TableName AS trg
INNER JOIN dbo.Origin AS src
ON ...';
EXEC sys.sp_executesql #sql; -- ,N'params', #params;
When you're selecting data, you can fool the parser a little bit by introducing constants to take the place of columns, taking advantage of SQL Server's desire to find a column reference even at a different scope than the syntax would suggest. I talk about this in Make SQL Server DMV Queries Backward Compatible. I don't know of any straightforward way to make that work with writes without dynamic SQL, as the parser does more strict checking there, so it's harder to fool.
Imagine you have these tables:
CREATE TABLE dbo.SourceTable(a int, b int, c int);
INSERT dbo.SourceTable(a,b,c) VALUES(1,2,3);
CREATE TABLE dbo.DestinationWithAllColumns(a int, b int, c int);
INSERT dbo.DestinationWithAllColumns(a,b,c) VALUES(1,2,3);
CREATE TABLE dbo.DestinationWithoutAllColumns(a int, b int);
INSERT dbo.DestinationWithoutAllColumns(a,b) VALUES(1,2);
You can write a SELECT against either of them that produces an int output column called c:
;WITH optional_columns AS
(
SELECT c = CONVERT(int, NULL)
)
SELECT trg.a, trg.b, trg.c
FROM optional_columns
CROSS APPLY
(SELECT a,b,c FROM dbo.DestinationWithAllColumns) AS trg
INNER JOIN dbo.SourceTable AS src ON src.a = trg.a;
Output:
a
b
c
1
2
3
;WITH optional_columns AS
(
SELECT c = CONVERT(int, NULL)
)
SELECT trg.a, trg.b, trg.c
FROM optional_columns
CROSS APPLY
(SELECT a,b,c FROM dbo.DestinationWithoutAllColumns) AS trg
INNER JOIN dbo.SourceTable AS src ON src.a = trg.a;
Output:
a
b
c
1
2
null
So far, so good. But as soon as you try and update:
;WITH optional_columns AS
(
SELECT c = CONVERT(int, NULL)
)
UPDATE trg SET trg.b = src.b, trg.c = src.c
FROM optional_columns
CROSS APPLY
(SELECT a,b,c FROM dbo.DestinationWithoutAllColumns) AS trg
INNER JOIN dbo.SourceTable AS src ON src.a = trg.a;
Msg 4421, Level 16, State 1
Derived table 'trg' is not updatable because a column of the derived table is derived or constant.
Example db<>fiddle

Combine sp result in select as column

I am trying to execute sp as sub query and treat result set of sp as column of outer query . Some thing like this
Select U.FirstName , (exec SomeSP ) as columnFromSP from User U
Is this possible i searched alot but found nothing on google.
Update
I cannot use #temp table because i am trying to do without #temp table
If you are able to convert your USP to a table value UDF, you will be use the UDF in your FROM statement.
CREATE FUNCTION dbo.SomeUDF
(
-- Add the parameters for the function here
#param varchar(1000)
)
RETURNS TABLE
AS
RETURN
(
SELECT #param as Value
)
GO
SELECT
a.Value,
'B' as Value2
FROM dbo.SomeUDF('ABC') a
Not possible, but you can work around it
Create a temp table & insert the results of the procedure into
it
Now join the User table with the temporary table and select the
columns you want from both tables
This assumes however, you have a joinable expression returned from the stored proc (one that you can match to a field in the user table). If the stored procedure on returns a single row, use a condition of 1=1 or something similar
-- Declare a temp table and column(for eg you have only 1 column)
CREATE TABLE #TEMP
(
FirstName VARCHAR(50)
)
-- The results after execution will be inserted to this table
INSERT INTO #TEMP
Exec SomeSP 'Params'
-- Select records from both tables in all combinations
SELECT U.FirstName , COL1 as columnFromSP
from User U
CROSS JOIN #TEMP

TSQL Subquery for Column Names?

Is it possible to use a set of query results for column names in a select statement?
Example, I have a table named TableA:
Column: Type:
KeyOne nvarchar(5)
KeyTwo nvarchar(5)
TableB is another table, whose column names might be stored in TableA.
Suppose TableB is like this:
Column: Type:
Val1 int
Val2 int
Is there any way I could do a query like this to get the columns?
SELECT (select TOP 1 KeyOne, KeyTwo FROM TableA)
FROM TableB
Another example using strings would be like this:
SELECT (select 'Val1', 'Val2')
FROM TableB
Is this possible in any way without concatenated SQL?
Unfortunately you can only do this with dynamic SQL, but it's pretty straightforward:
DECLARE #cols VARCHAR(MAX) = (SELECT TOP 1 KeyOne+','+KeyTwo FROM TableA)
,#sql VARCHAR(MAX)
SET #sql = 'SELECT '+#cols+' FROM TableB'
EXEC (#sql)
You can read table column names dynamically from sys.columns system views or using other management views
select name from sys.columns where object_id = object_id(N'TableName')
Then by creating a dynamic SQL query you can create your own select

Is there a way to find all invalid columns that are referenced in a view using SQL Server 2012?

I have inherited a large database project with thousands of views.
Many of the views are invalid. They reference columns that no longer exist. Some of the views are very complex and reference many columns.
Is there an easy way to track down all the incorrect columns references?
This answer finds the underlying columns that were originally defined in the views by looking at sys.views, sys.columns and sys.depends (to get the underlying column if the column has been aliased). It then compares this with the data held in INFORMATION_Schema.VIEW_COLUMN_USAGE which appears to have the current column usage.
SELECT SCHEMA_NAME(v.schema_id) AS SchemaName,
OBJECT_NAME(v.object_id) AS ViewName,
COALESCE(alias.name, C.name) As MissingUnderlyingColumnName
FROM sys.views v
INNER JOIN sys.columns C
ON C.object_id = v.object_id
LEFT JOIN sys.sql_dependencies d
ON d.object_id = v.object_id
LEFT JOIN sys.columns alias
ON d.referenced_major_id = alias.object_id AND c.column_id= alias.column_id
WHERE NOT EXISTS
(
SELECT * FROM Information_Schema.VIEW_COLUMN_USAGE VC
WHERE VIEW_NAME = OBJECT_NAME(v.object_id)
AND VC.COLUMN_NAME = COALESCE(alias.name, C.name)
AND VC.TABLE_SCHEMA = SCHEMA_NAME(v.schema_id)
)
For the following view:
create table test
( column1 varchar(20), column2 varchar(30))
create view vwtest as select column1, column2 as column3 from test
alter table test drop column column1
The query returns:
SchemaName ViewName MissingUnderlyingColumnName
dbo vwtest column1
This was developed with the help of this Answer
UPDATED TO RETRIEVE ERROR DETAILS
So this answer gets you what you want but it isn't the greatest code.
A cursor is used (yes I know :)) to execute a SELECT from each view in a TRY block to find ones that fail. Note I wrap each statement with a SELECT * INTO #temp FROM view X WHERE 1 = 0 this is to stop the EXEC returning any results and the 1=0 is so that SQL Server can optimize the query so that it is in effect a NO-OP.
I then return a list of any views whose sql has failed.
I haven't performed lots of testing on this, but it appears to work. I would like to get rid of the execution of each SELECT from View.
So here it is:
DECLARE curView CURSOR FOR
SELECT v.name AS ViewName
FROM sys.views v
INNER JOIN sys.sql_modules m
on v.object_id = m.object_id
OPEN curView
DECLARE #viewName SYSNAME
DECLARE #failedViews TABLE
(
FailedViewName SYSNAME,
ErrorMessage VARCHAR(MAX)
)
FETCH NEXT FROM curView
INTO #ViewName
WHILE ##FETCH_STATUS = 0
BEGIN
BEGIN TRY
exec ('SELECT * INTO #temp FROM ' + #viewName + ' WHERE 1=0' )
END TRY
BEGIN CATCH
INSERT INTO #failedViews VALUES (#viewName, ERROR_MESSAGE())
END CATCH
FETCH NEXT FROM curView
INTO #ViewName
END
CLOSE curView
DEALLOCATE curView
SELECT *
FROM #failedViews
An example of an ERROR returned is:
FailedViewName ErrorMessage
--------------- -------------
vwtest Invalid column name 'column1'.
You could use system tables get information.
SELECT v.VIEW_NAME,v.TABLE_CATALOG,v.TABLE_SCHEMA,v.TABLE_NAME,v.COLUMN_NAME
from INFORMATION_SCHEMA.VIEW_COLUMN_USAGE v
left outer join INFORMATION_SCHEMA.COLUMNS c
ON v.TABLE_CATALOG=c.TABLE_CATALOG AND v.TABLE_SCHEMA=c.TABLE_SCHEMA AND v.TABLE_NAME=c.TABLE_NAME AND v.COLUMN_NAME=c.COLUMN_NAME
WHERE c.TABLE_NAME IS NULL
ORDER BY v.VIEW_NAME

SQL query for finding all tables ROWS with two columns in them

I have a DataBase with around +100 tables, like half of tables have column A & column B.
My question is, Can I query all tables that have this columns with a specific values e.g.
SELECT * FROM DATABASE
WHERE
EACHTABLE HAS COLUMN A = 21 //only if table has columns and then values
AND
COLUMN B = 13
I am not sure how exact I will do it, nothing is coming up on google either
You can use the undocumented MS stored procedure sp_MSforeachtable, if you fancy living life recklessly:
create table T1 (
ColumnA int not null,
ColumnB int not null
)
go
create table T2 (
ColumnA int not null,
Column2 int not null
)
go
create table T3 (
Column1 int not null,
ColumnB int not null
)
go
create table T4 (
ColumnA int not null,
ColumnB int not null
)
go
insert into T1 values (1,2);
insert into T2 values (3,4);
insert into T3 values (5,6);
insert into T4 values (7,8);
go
create table #Results (TableName sysname,ColumnA int,ColumnB int)
exec sp_MSforeachtable 'insert into #Results select ''?'',ColumnA,ColumnB from ?',
#whereand = ' and syso.object_id in (select object_id from sys.columns where name=''ColumnA'') and syso.object_id in (select object_id from sys.columns where name=''ColumnB'')'
select * from #Results
drop table #Results
Result:
TableName ColumnA ColumnB
------------------------------------- ----------- -----------
[dbo].[T1] 1 2
[dbo].[T4] 7 8
By default, sp_MSforeachtable will, as its name implies, perform the same task for each table in the database. However, one optional parameter to this procedure, called #Whereand, can be used to modify the WHERE clause of the internal query that enumerates the tables in the database. It helps to know that this internal query has already established two aliases to some of the system views. o is an alias for sysobjects (the legacy system view). syso is an alias for sys.all_objects (a more modern system view).
Once sp_MSforeachtable has decided which tables to run against, it will execute the query given to it as its first parameter. But, it will replace ? with the schema and table name (? is the default replacement character. This can be changed as needed)
In this case, I chose to create a temp table, then have each selected table store its results into this temp table, and after sp_MSforeachtable has finished running, to select the combined results out with no further processing.
There is a similar (and similarly undocumented) procedure called sp_MSforeachdb which will access each user database on the server. These can even be combined (although you have to be careful with doubling up ' quote characters twice, at times). However, there's no equivalent sp_MSforeachcolumn.
Try this:
select t.name from sys.objects t inner join sys.columns c
on t.name=OBJECT_NAME(c.object_id)
where t.type='U'
and c.name in('col1','col2')
group by t.name
having COUNT(*) = 2
order by 1
Then you just loop through all the tables and fine the values for these columns.
Like
Declare #out TABLE(tblname varchar(100))
if exists(select * from tbl1 where col1='21' and col2='22')
BEGIN
INSERT INTO #out
select tbl1
END
You can try like this using dynamic query.
select 'select * from '+table_name+ ' where'+column_name+'=21'
from information_schema.columns where column_name = 'A'
I suggest to use two steps:
First, find out all tables in your database that have these two columns and use it for a temporal derived table. For I am not an expert in SQL-Server 2008 I recommend to have a look at the whitepages.
The expression might look like this:
SELECT tablename
FROM information_schema.tables sdbt
WHERE "column a" IN
(SELECT columns
FROM information_schema.columns col
WHERE col.tablename = sdbt.tablename)
Second, use a expresssion to filter the results according to your demanded values.
This command should do the trick in one go, only for column A, amend accordingly to include any other columns you need:
exec sp_MSforeachtable
#command1=N'SELECT * FROM ? WHERE A = 21',
#whereand=' and o.name IN (SELECT TABLE_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE COLUMN_NAME = ''A'') '