I have a table that contains many rows of SQL commands that make up a single SQL statement (to which I am grateful for this answer, step 5 here)
I have followed the example in this answer and now have a table of SQL - each row is a line of SQL that build a query. I can copy and paste the contents of this table into a new query window and get the results however due to my lack of SQL knowledge I am not sure how I go about copying the contents of the table into a string variable which I can then execute.
Edit: The SQL statement in my table comprises of 1 row per each line of the statement i.e.
Row1: SELECT * FROM myTable
Row2: WHERE
Row3: col = #value
This statement if copied into a VARCHAR(MAX) exceeds the MAX limit.
I look forward to your replies. in the mean time I will try myself.
Thank you
You can use coalesce to concatenate the contents of a column into a string, e.g.
create table foo (sql varchar (max));
insert foo (sql) values ('select name from sys.objects')
insert foo (sql) values ('select name from sys.indexes')
declare #sql_output varchar (max)
set #sql_output = '' -- NULL + '' = NULL, so we need to have a seed
select #sql_output = -- string to avoid losing the first line.
coalesce (#sql_output + sql + char (10), '')
from foo
print #sql_output
Note: untested, just off the top of my head, but a working example of this should produce the following output:
select name from sys.objects
select name from sys.indexes
You can then execute the contents of the string with exec (#sql_output) or sp_executesql.
You can try something like this
DECLARE #TABLE TABLE(
SqlString VARCHAR(MAX)
)
INSERT INTO #TABLE (SqlString) SELECT 'SELECT 1'
DECLARE #SqlString VARCHAR(MAX)
SELECT TOP 1 #SqlString = SqlString FROM #TABLE
EXEC (#SqlString)
Concatenate string from multiple rows
DECLARE #Table TABLE(
ID INT,
Val VARCHAR(50)
)
INSERT INTO #Table (ID,Val) SELECT 1, 'SELECT *'
INSERT INTO #Table (ID,Val) SELECT 2, 'FROM YourTable'
INSERT INTO #Table (ID,Val) SELECT 3, 'WHERE 1 = 1'
DECLARE #SqlString VARCHAR(MAX)
--Concat
SELECT DISTINCT
#SqlString =
(
SELECT tIn.Val + ' '
FROM #Table tIn
ORDER BY ID
FOR XML PATH('')
)
FROM #Table t
PRINT #SqlString
if you want to execute a string of sql then use Exec() or sp_executeSql
Related
I'm trying to build a stored procedure that will query multiple database depending on the databases required.
For example:
SP_Users takes a list of #DATABASES as parameters.
For each database it needs to run the same query and union the results together.
I believe a CTE could be my best bet so I have something like this at the moment.
SET #DATABASES = 'DB_1, DB_2' -- Two databases in a string listed
-- I have a split string function that will extract each database
SET #CURRENT_DB = 'DB_1'
WITH UsersCTE (Name, Email)
AS (SELECT Name, Email
FROM [#CURRENT_DB].[dbo].Users),
SELECT #DATABASE as DB, Name, Email
FROM UsersCTE
What I don't want to do is hard code the databases in the query. The steps I image are:
Split the parameter #DATABASES to extract and set the #CURRENT_DB Variable
Iterate through the query with a Recursive CTE until all the #DATABASES have been processed
Union all results together and return the data.
Not sure if this is the right approach to tackling this problem.
Using #databases:
As mentioned in the comments to your question, variables cant be used to dynamically select a database. Dynamic sql is indicated. You can start by building your template sql statement:
declare #sql nvarchar(max) =
'union all ' +
'select ''#db'' as db, name, email ' +
'from [#db].dbo.users ';
Since you have sql server 2016, you can split using the string_split function, with your #databases variable as input. This will result in a table with 'value' as the column name, which holds the database names.
Use the replace function to replace #db in the template with value. This will result in one sql statement for each database you passed into #databases. Then, concatenate the statements back together. Unfortunately, in version 2016, there's no built in function to do that. So we have to use the famous for xml trick to join the statements, then we use .value to convert it to a string, and finally we use stuff to get rid of the leading union all statement.
Take the results of the concatenated output, and overwrite the #sql variable. It is ready to go at this point, so execute it.
I do all that is described in this code:
declare #databases nvarchar(max) = 'db_1,db_2';
set #sql = stuff(
(
select replace(#sql, '#db', value)
from string_split(#databases, ',')
for xml path(''), type
).value('.[1]', 'nvarchar(max)')
, 1, 9, '');
exec(#sql);
Untested, of course, but if you print instead of execute, it seems to give the proper sql statement for your needs.
Using msForEachDB:
Now, if you didn't want to have to know which databases had 'users', such as if you're in an environment where you have a different database for every client, you can use sp_msForEachDb and check the structure first to make sure it has a 'users' table with 'name' and 'email' columns. If so, execute the appropriate statement. If not, execute a dummy statement. I won't describe this one, I'll just give the code:
declare #aggregator table (
db sysname,
name int,
email nvarchar(255)
);
insert #aggregator
exec sp_msforeachdb '
declare #sql nvarchar(max) = ''select db = '''''''', name = '''''''', email = '''''''' where 1 = 2'';
select #sql = ''select db = ''''?'''', name, email from ['' + table_catalog + ''].dbo.users''
from [?].information_schema.columns
where table_schema = ''dbo''
and table_name = ''users''
and column_name in (''name'', ''email'')
group by table_catalog
having count(*) = 2
exec (#sql);
';
select *
from #aggregator
I took the valid advice from others here and went with this which works great for what I need:
I decided to use a loop to build the query up. Hope this helps someone else looking to do something similar.
CREATE PROCEDURE [dbo].[SP_Users](
#DATABASES VARCHAR(MAX) = NULL,
#PARAM1 VARCHAR(250),
#PARAM2 VARCHAR(250)
)
BEGIN
SET NOCOUNT ON;
--Local variables
DECLARE
#COUNTER INT = 0,
#SQL NVARCHAR(MAX) = '',
#CURRENTDB VARCHAR(50) = NULL,
#MAX INT = 0,
#ERRORMSG VARCHAR(MAX)
--Check we have databases entered
IF #DATABASES IS NULL
BEGIN
RAISERROR('ERROR: No Databases Provided,
Please Provide a list of databases to execute procedure. See stored procedure:
[SP_Users]', 16, 1)
RETURN
END
-- SET Number of iterations based on number of returned databases
SET #MAX = (SELECT COUNT(*) FROM
(SELECT ROW_NUMBER() OVER (ORDER BY i.value) AS RowNumber, i.value
FROM dbo.udf_SplitVariable(#DATABASES, ',') AS i)X)
-- Build SQL Statement
WHILE #COUNTER < #MAX
BEGIN
--Set the current database
SET #CURRENTDB = (SELECT X.Value FROM
(SELECT ROW_NUMBER() OVER (ORDER BY i.value) AS RowNumber, i.value
FROM dbo.udf_SplitVariable(#DATABASES, ',') AS i
ORDER BY RowNumber OFFSET #COUNTER
ROWS FETCH NEXT 1 ROWS ONLY) X);
SET #SQL = #SQL + N'
(
SELECT Name, Email
FROM [' + #CURRENTDB + '].[dbo].Users
WHERE
(Name = #PARAM1 OR #PARAM1 IS NULL)
(Email = #PARAM2 OR #PARAM2 IS NULL)
) '
+ N' UNION ALL '
END
PRINT #CURRENTDB
PRINT #SQL
SET #COUNTER = #COUNTER + 1
END
-- remove last N' UNION ALL '
IF LEN(#SQL) > 11
SET #SQL = LEFT(#SQL, LEN(#SQL) - 11)
EXEC sp_executesql #SQL, N'#CURRENTDB VARCHAR(50),
#PARAM1 VARCHAR(250),
#PARAM2 VARCHAR(250)',
#CURRENTDB,
#PARAM1 ,
#PARAM2
END
Split Variable Function
CREATE FUNCTION [dbo].[udf_SplitVariable]
(
#List varchar(8000),
#SplitOn varchar(5) = ','
)
RETURNS #RtnValue TABLE
(
Id INT IDENTITY(1,1),
Value VARCHAR(8000)
)
AS
BEGIN
--Account for ticks
SET #List = (REPLACE(#List, '''', ''))
--Account for 'emptynull'
IF LTRIM(RTRIM(#List)) = 'emptynull'
BEGIN
SET #List = ''
END
--Loop through all of the items in the string and add records for each item
WHILE (CHARINDEX(#SplitOn,#List)>0)
BEGIN
INSERT INTO #RtnValue (value)
SELECT Value = LTRIM(RTRIM(SUBSTRING(#List, 1, CHARINDEX(#SplitOn, #List)-1)))
SET #List = SUBSTRING(#List, CHARINDEX(#SplitOn,#List) + LEN(#SplitOn), LEN(#List))
END
INSERT INTO #RtnValue (Value)
SELECT Value = LTRIM(RTRIM(#List))
RETURN
END
I am using SQL Server 2008 R2 version. I have a simple table which has multiple columns. One of the column in EmpId which is of type nvarchar(50)
I am writing a stored procedure in which I receive an input which can have one of the following values.
Single EmpId: '12345'
Multiple EmpId's comma separated: '12345, 56789, 98987'
null
What I want:
If empid is a single empId just return
select *
from table_name
where EmpId = #empId
If empid is multiple comma-separated values, just return
select *
from table_name
where EmpId in (select * from dbo.splitstring(#empId))
if empId is null just return
Select *
from table_name
No need for where clause.
To cover all the three condition this is what I am trying:
DECLARE #empId nvarchar(2000)
SET #empId = '97050001,97050003, 97050004'
SELECT TOP 10 empId
FROM Employee
WHERE empId in (COALESCE((select * from dbo.splitstring(#empId)),[empId]))
I am getting following error:
Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.
I understand the error. COALESCE() is expecting a single value but when I am getting comma separated values, splitstring function returns multiple values.
I do not want to build a dynamic query, so besides duplicating the code with if else block where I check if empId is null run select * from table_name else run select * from table name where empId in (). What options do I have?
To split comma-separated string into table, I am using this function:
CREATE FUNCTION dbo.splitstring ( #stringToSplit VARCHAR(MAX) )
RETURNS
#returnList TABLE ([Name] [nvarchar] (500))
AS
BEGIN
DECLARE #name NVARCHAR(255)
DECLARE #pos INT
WHILE CHARINDEX(',', #stringToSplit) > 0
BEGIN
SELECT #pos = CHARINDEX(',', #stringToSplit)
SELECT #name = SUBSTRING(#stringToSplit, 1, #pos-1)
INSERT INTO #returnList
SELECT #name
SELECT #stringToSplit = SUBSTRING(#stringToSplit, #pos+1, LEN(#stringToSplit)-#pos)
END
INSERT INTO #returnList
SELECT #stringToSplit
RETURN
END
Try this with a bit more sophisticated version of split string fuction.
CREATE PROCEDURE myProc
#EmpId NVARCHAR(50) = NULL
AS
BEGIN
SET NOCOUNT ON;
DECLARE #Sql NVARCHAR(MAX);
SET #Sql = N' SELECT * FROM Table_Name WHERE 1 = 1'
+ CASE WHEN #EmpId IS NOT NULL THEN
N' AND empId IN ( SELECT Split.a.value(''.'', ''VARCHAR(100)'') empId
FROM (
SELECT Cast (''<X>''
+ Replace(#EmpId, '','', ''</X><X>'')
+ ''</X>'' AS XML) AS Data
) AS t CROSS APPLY Data.nodes (''/X'') AS Split(a)
) ' ELSE N'' END
Exec sp_executesql #Sql
,N'#EmpId NVARCHAR(50)'
,#EmpId
END
This version will perform better because
More efficient string splitting.
Better execution plan because of the parameterised execution plan caching because of the sp_executesql .
Depends on what you need:-
I do not want to build dynamic query, so besides duplicating the code
with if else block where I check if empId is null run select * from
table_name else run select * from table name where empId in ()
and for avoiding the duplicate, use the next approach:-
DECLARE #empId nvarchar(2000)
set #empId = '97050001,97050003,97050004'
if CHARINDEX(',',#empId) > 0 -- multiple Values
begin
set #empId = '''' + replace (#empId,',',''',''') + ''''
end
else if #empId is null
begin
set #empId = 'select empId from Employee'
end
exec ('select top 10 empId from Employee where empId in (' + #empId + ')' )
This approach handles the three cases:-
Passing a single value.
Passing multiple Value.
Passing a Null.
Case 1 and 2 can both be handled for the code you have already written for Case 2. You just need to add an OR condition for Case 3.
select *
from table_name
where #empId is NULL
or EmpId in (select * from dbo.splitstring(#empId))
That being said, IN clauses wrapping select statements are generally bad practice for the following reasons
They are slower than joins when the select statement returns many rows
Joins are more idiomatic
In your case, if there are only a few rows returned by splitstring it likely won't make much difference, but the following would be a more general approach to this kind of query.
select *
from table_name t
left join dbo.splitstring(#empId) s
on t.EmpId = s.Name
where #empId is NULL
or s.Name is not NULL
Feel free to check the execution plan for your query and profile to see which one is quicker, though your initial implementation should be fine. To quote Donald Knuth, "premature optimization is the root of all evil."
Update
After double checking the execution plans used in the cases when #empId is null and non null, it looks like the query above will always use the same execution plan, i.e. to join against the contents of the in clause, regardless of whether #empId is null. This is probably not ideal, as pointed out by #m-ali.
To ensure the proper execution plan in each case, you can separate this into two queries:
IF #empId is NULL
select *
from table_name
ELSE
select *
from table_name
where EmpId in (select * from dbo.splitstring(#empId))
I've verified the proper execution plan in either case in SSMS.
Disclaimer: I haven't profiled it but the string splitting suggested by #m-ali is also likely faster.
I have several tables with common table names. I want to select all data from them without specifying all tables and union them. I'm thinking of using information_schema.tables to accomplish this.
Tables:
tbl_20160201
tbl_20160202
tbl_20160203
tbl_20160204
tbl_20160205
Query:
SELECT *
FROM (
SELECT *
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE 'tbl_201602%'
) a
However, this query only returns the table names and not the data in the tables. I need to union all the tables included in the query. Thank you.
Assuming these tables have the same number of columns and data types, you can use dynamic sql:
DECLARE #sql NVARCHAR(MAX) = N'';
SELECT #sql = #sql +
'SELECT * FROM ' + TABLE_NAME + ' UNION ALL' + CHAR(10)
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE 'tbl_201602%';
SELECT #sql = SUBSTRING(#sql,1, LEN(#sql) - 11);
PRINT(#sql)
EXEC (#sql)
Otherwise, you'll get an error saying:
All queries combined using a UNION, INTERSECT or EXCEPT operator must
have an equal number of expressions in their target lists
Below query might help you :-
DECLARE #SQL VARCHAR(max)
DECLARE #T as sysname
-- Make sure below temporary table structure same as the tables e.g tbl_201602 which you want to union
declare #TT as Table(
Col1 [decimal](18, 2) NOT NULL,
Col2 [date] NOT NULL,
Col3 [varchar](200) NOT NULL
)
DECLARE TName CURSOR FORWARD_ONLY STATIC FOR
select TABLE_NAME
from
information_schema.tables where TABLE_NAME like 'tbl_201602%'
OPEN TName
FETCH NEXT FROM TName INTO #T
WHILE ##FETCH_STATUS = 0
BEGIN
SELECT #SQL = 'select * from' + ' ' + #T
INSERT INTO #TT
EXEC(#SQL)
FETCH NEXT FROM TName INTO #T
END
CLOSE TName
DEALLOCATE TName
select * from #TT
This will give the union of all tables in a single temporary table #TT
NOTE : Just make sure that all comman tables are having same no of columns and in same ordering, otherwise it may raise error
I need to select from table where the the table name suffix are from another table, like this :
declare #value nvarchar(3),
#table nvarchar(1000),
#SQLST NVARCHAR(255);
set #value = N'select column1 from tableX';
EXEC #value
set #table ='partoftableY'
Set #SQLST ='select * from' +#tabel + #value -- here I create the table name
However there are multiple values in TableX (0-999) and so this doesn't work. Do I need a For Each type construct.
here in an example I created with two tables (partoftableY1 & partoftableY2) with different data in each
/*
create table tableX (column1 int);
insert into tablex
select 1
union all select 2;
create table partoftableY1 (data nvarchar(50));
create table partoftableY2 (data nvarchar(50));
insert into partoftableY1 select 'hey 1 here';
insert into partoftableY2 select 'hey 2 here';
*/
declare #sql nvarchar(max)
-- use the ability of SQL to build up string of all the sql you need to run
set #sql = 'select data from (select '''' as data'
select #sql = COALESCE(#sql + ' union all ', '')
+ 'select data from partoftableY'
+ cast(column1 as nvarchar(4)) from tableX
select #sql = #sql + ') X where data <>'''''
-- DEBUG for seeing what SQL you created
print #sql
-- Now execute the SQL
exec sp_executesql #sql= #sql
which gives me the results of
hey 1 here
hey 2 here
You will need to adjust it for types of your data, but this should give you the main idea
For reference here is the sql that was created and executed:
select data
from (
select '' as data
union all select data from partoftableY1
union all select data from partoftableY2
) X
where data <>''
N.B.
I put formatted it for easier reading, as it's actually created as one long line
I used selet data and not select * as the number of columns needs to be the same for each select in the union. You will need to select the columns you need and then make changes ensure that all the columns in the selects in the union are the same.
There is a dummy select at the top of the union to make the union code easy - no conditionals needed as whether the union all needs to present
I used the out select over the whole union to enable you to get sid of the dummy select
You can try this
DECLARE #SQLST NVARCHAR(max)='';
DECLARE #select nvarchar(max)=N'select * from partoftableY'
DECLARE #union nvarchar(max)=N'
UNION ALL
'
SELECT #SQLST=#select+column1+#union
FROM tablex
SELECT #SQLST=substring(#SQLST,1,LEN(#SQLST)-11)
EXEC sp_executesql #SQLST
The code is as follows:
ALTER PROCEDURE dbo.pdpd_DynamicCall
#SQLString varchar(4096) = null
AS
Begin
create TABLE #T1 ( column_1 varchar(10) , column_2 varchar(100) )
insert into #T1
execute ('execute ' + #SQLString )
select * from #T1
End
The problem is that I want to call different procedures that can give back different columns.
Therefore I would have to define the table #T1 generically.
But I don't know how.
Can anyone help me on this problem?
Try:
SELECT into #T1 execute ('execute ' + #SQLString )
And this smells real bad like an sql injection vulnerability.
correction (per #CarpeDiem's comment):
INSERT into #T1 execute ('execute ' + #SQLString )
also, omit the 'execute' if the sql string is something other than a procedure
You can define a table dynamically just as you are inserting into it dynamically, but the problem is with the scope of temp tables. For example, this code:
DECLARE #sql varchar(max)
SET #sql = 'CREATE TABLE #T1 (Col1 varchar(20))'
EXEC(#sql)
INSERT INTO #T1 (Col1) VALUES ('This will not work.')
SELECT * FROM #T1
will return with the error "Invalid object name '#T1'." This is because the temp table #T1 is created at a "lower level" than the block of executing code. In order to fix, use a global temp table:
DECLARE #sql varchar(max)
SET #sql = 'CREATE TABLE ##T1 (Col1 varchar(20))'
EXEC(#sql)
INSERT INTO ##T1 (Col1) VALUES ('This will work.')
SELECT * FROM ##T1
Hope this helps,
Jesse
Be careful of a global temp table solution as this may fail if two users use the same routine at the same time as a global temp table can be seen by all users...
create a global temp table with a GUID in the name dynamically. Then you can work with it in your code, via dyn sql, without worry that another process calling same sproc will use it. This is useful when you dont know what to expect from the underlying selected table each time it runs so you cannot created a temp table explicitly beforehand. ie - you need to use SELECT * INTO syntax
DECLARE #TmpGlobalTable varchar(255) = 'SomeText_' + convert(varchar(36),NEWID())
-- select #TmpGlobalTable
-- build query
SET #Sql =
'SELECT * INTO [##' + #TmpGlobalTable + '] FROM SomeTable'
EXEC (#Sql)
EXEC ('SELECT * FROM [##' + #TmpGlobalTable + '] ')
EXEC ('DROP TABLE [##' + #TmpGlobalTable + ']')
PRINT 'Dropped Table ' + #TmpGlobalTable
INSERT INTO #TempTable
EXEC(#SelectStatement)
Try Below code for creating temp table dynamically from Stored Procedure Output using T-SQL
declare #ExecutionName varchar(1000) = 'exec [spname] param1,param2 '
declare #sqlStr varchar(max) = ''
declare #tempTableDef nvarchar(max) =
(
SELECT distinct
STUFF(
(
SELECT ','+a.[name]+' '+[system_type_name]
+'
' AS [text()]
FROM sys.dm_exec_describe_first_result_set (#ExecutionName, null, 0) a
ORDER BY a.column_ordinal
FOR XML PATH ('')
), 1, 1, '') tempTableDef
FROM sys.dm_exec_describe_first_result_set (#ExecutionName, null, 0) b
)
IF ISNULL(#tempTableDef ,'') = '' RAISERROR( 'Invalid SP Configuration. At least one column is required in Select list of SP output.',16,1) ;
set #tempTableDef='CREATE TABLE #ResultDef
(
' + REPLACE(#tempTableDef,'
','') +'
)
INSERT INTO #ResultDef
' + #ExecutionName
Select #sqlStr = #tempTableDef +' Select * from #ResultDef '
exec(#sqlStr)
DECLARE #EmpGroup INT =3 ,
#IsActive BIT=1
DECLARE #tblEmpMaster AS TABLE
(EmpCode VARCHAR(20),EmpName VARCHAR(50),EmpAddress VARCHAR(500))
INSERT INTO #tblEmpMaster EXECUTE SPGetEmpList #EmpGroup,#IsActive
SELECT * FROM #tblEmpMaster
CREATE PROCEDURE dbo.pdpd_DynamicCall
AS
DECLARE #SQLString_2 NVARCHAR(4000)
SET NOCOUNT ON
Begin
--- Create global temp table
CREATE TABLE ##T1 ( column_1 varchar(10) , column_2 varchar(100) )
SELECT #SQLString_2 = 'INSERT INTO ##T1( column_1, column_2) SELECT column_1 = "123", column_2 = "MUHAMMAD IMRON"'
SELECT #SQLString_2 = REPLACE(#SQLString_2, '"', '''')
EXEC SP_EXECUTESQL #SQLString_2
--- Test Display records
SELECT * FROM ##T1
--- Drop global temp table
IF OBJECT_ID('tempdb..##T1','u') IS NOT NULL
DROP TABLE ##T1
End
Not sure if I understand well, but maybe you could form the CREATE statement inside a string, then execute that String? That way you could add as many columns as you want.