Best way to loop through a table with queries and execute them - sql-server

I have a table which contains a column with queries. I need to execute them one by one and save the result in another table. What is the best way to implement this logic inside a stored procedure?
So for example the table looks like this:
id query
1 select count(*) from table_a
2 select count(*) from table_b
A cursor can be an option, but is there another way?

You can try performing this task with a combination of FOR XML and dynamic SQL:
DECLARE #mySchema NVARCHAR(10) = 'dbo'
DECLARE #stmt NVARCHAR(MAX) = '';
SELECT #stmt = (SELECT stmt FROM(
SELECT STUFF((
SELECT ' UNION ALL SELECT ' + CHAR(39) + s.name + '_' + o.name + CHAR(39) + ' AS TabName, COUNT(*) AS Cnt FROM ' + s.name + '.' + o.name
FROM sys.all_objects o
JOIN sys.schemas s ON s.schema_id = o.schema_id
WHERE o.type = 'U'
AND s.name = #mySchema
FOR XML PATH('')
), 1, 11, '') AS stmt
) xm)
EXEC(#stmt)
However, if only certain tables are required you will have to modify the query a little. Furthermore you can modify the query to get your selects from the table and join them via UNION ALL...

Related

SQL Server Query to get Data from a Table where each row is a Table

I have a schema where I have multiple tables some with time and some without it. So I created a query where I have listed 3 tables say which has time like this :
WITH CTE AS
(
SELECT
CONCAT(schema_name(t.schema_id), '.', t.name) AS table_name,
c.name AS 'time'
FROM
sys.tables t
INNER JOIN
sys.columns c ON c.object_id = t.object_id
WHERE
schema_name(t.schema_id) = 'Prod'
AND c.name = 'mytime'
)
SELECT * FROM CTE
Now my output looks like ( I am showing 3 rows for the example):
Table O
table_name time
--------------------------
Prod.tableA mytime
Prod.tableB mytime
Prod.tableC mytime
So usually what I want is to get the max(mytime) from each Table/Schema combination . So for a single table I can do
SELECT MAX(mytime)
FROM Prod.tableA
However in this case I want to generate this from table O for each table and my output should look like:
Table F
table_name mymax(time)
--------------------------------------------
Prod.tableA max(mytime) from Prod.tableA
Prod.tableB max(mytime) from Prod.tableA
Prod.tableC max(mytime) from Prod.tableA
How to achieve this using another select/variable declaration etc? Any help or ideas will be extremely appreciated. Thanks in anticipation.
Can this help? You still have a bit of work, check if the output is what you like and then uncomment the exec.
DECLARE #SchemaName NVARCHAR(100) = 'foo',
#ColumnName NVARCHAR(100) = 'bar',
#sql NVARCHAR(max)
SELECT #SchemaName + '.'+ t.name AS [Schema.Table],'( SELECT MAX(' + #ColumnName + ') FROM ['+ #SchemaName +'].['+t.name+']) ' AS MaxValue
FROM sys.tables t
JOIN sys.schemas s ON t.schema_id = s.schema_id
WHERE s.name = #SchemaName
-------
SELECT #sql =
STUFF((
SELECT 'UNION ALL ' + 'SELECT ' + '''' + '[' + ISNULL(#SchemaName,'') + '].['+ t.name + ']' + '''' + ' AS [Schema.Table] ,( SELECT MAX(' + #ColumnName + ') FROM ['+ #SchemaName +'].['+t.name+']) AS Max' + #ColumnName + ' '
FROM sys.tables t
JOIN sys.schemas s ON t.schema_id = s.schema_id
WHERE s.name = #SchemaName
for xml path('')
),1,10,'')
PRINT #sql
--EXEC(#sql)

What is the T-SQL syntax to exclude a duplicate column in the output when joining 2 tables?

I am using SQL Server 2014 and I have the following T-SQL query which joins 2 tables:
SELECT a.*, b.* FROM TEMP a
INNER JOIN Extras b ON b.ResaID = a.ResaID
I would like to pull ALL the columns from TEMP and all the columns from "Extras" with the exception of the ResaID column as it is already included in a.* in the above query. Basically, I want to pull a.* + b.* (excluding b.ResaID).
I know I can write the query in the form:
Select a.*, b.column2, b.column3,...
but since b.* has got around 40 columns, is there a way to write the query in a more simplified way to exclude b.ResaID, rather than specify each of the columns in the "Extras" table?
Unfortunately, there is no such syntax. You could either use asterisks (*) and just ignore the duplicated column in your code, or explicitly list the columns you need.
You should create a view and select the columns you need from that view. Here is a script that will generate that view for you:
DECLARE #table1 nvarchar(20) = 'temp'
DECLARE #table1key nvarchar(20) = 'ResaID'
DECLARE #table2 nvarchar(20) = 'Extras'
DECLARE #table2key nvarchar(20) = 'ResaID'
DECLARE #viewname varchar(20) = 'v_myview'
DECLARE #sql varchar(max) = ''
SELECT #sql += '], a.[' + column_name
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = #table1
SELECT #sql += '], b.[' + column_name
FROM
(
SELECT column_name
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = #table2
EXCEPT
SELECT column_name
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = #table1
) x
SELECT
#sql = 'CREATE view ' +#viewname+ ' as SELECT '
+ STUFF(#sql, 1, 3, '') + '] FROM ['
+#table1+ '] a JOIN ['+ #table2
+'] b ON ' + 'a.' + #table1key + '=b.' + #table2key
EXEC(#sql)
You can simply solve this using a dynamic sql query.
DECLARE #V_SQL AS NVARCHAR(2000)='' --variable to store dynamic query
,#V_TAB1 AS NVARCHAR(200)='TEMP' --First Table
,#V_TAB2 AS NVARCHAR(200)='Extras' --Second Table
,#V_CONDITION AS NVARCHAR(2000)='A.ResaID = B.ResaID' --Conditions
SELECT #V_SQL = STUFF(
( SELECT ', '+TCOL_NAME
FROM
( SELECT 'A.'+S.NAME AS TCOL_NAME
FROM SYSCOLUMNS AS S
WHERE OBJECT_NAME(ID) = #V_TAB1
UNION ALL
SELECT 'B.'+S.NAME
FROM SYSCOLUMNS AS S
WHERE OBJECT_NAME(ID) = #V_TAB2
AND S.NAME NOT IN (SELECT S.NAME
FROM SYSCOLUMNS AS S
WHERE OBJECT_NAME(ID) = #V_TAB1)
) D
FOR XML PATH('')
),1,2,'')
EXECUTE ('SELECT '+#V_SQL+'
FROM '+#V_TAB1+' AS A
INNER JOIN '+#V_TAB2+' AS B ON '+#V_CONDITION+' ')

SQL Server - is there option to generate insert script just to not null columns (required columns)?

I have a big table and for tests I would like to generate a script from SQL Server just for these columns. I think there isn't this option... just a full script and I'll need to remove each one.
Just to confirm.
Thanks! who knows.
You can set up the statement querying the system tables - probably more trouble than it's worth, but still doable:
DECLARE #tablename VARCHAR(255) = 'UnprocessedQueueData';
WITH columns
AS ( SELECT STUFF(( SELECT ',' + c.name
FROM sys.columns c
INNER JOIN sys.tables t ON t.object_id = c.object_id
WHERE t.name = #tablename
AND c.is_nullable = 0
AND c.is_identity = 0
ORDER BY c.name
FOR
XML PATH('')
), 1, 1, '') col
)
SELECT 'INSERT INTO ' + t.name + ' ( ' + columns.col
+ ' ) SELECT * FROM OtherTable;'
FROM sys.tables t
CROSS JOIN columns
WHERE t.name = #tablename

Using single select query get the Minimum,Maximum values of Identity Columns of all the tables in a Database

Using a single select query, I need to get the Minimum and Maximum values of Identity Columns along with the other columns specified in the query below, for all tables in a given database.
This is what I've been able to code to get a list of tables and their identity columns:
Select so.name as TableName
, sic.name as ColumnName
, i.Rows Count_NumberOfRecords
, IDENT_CURRENT(so.name)+IDENT_INCR(so.name) as NextSeedValue
from sys.identity_columns sic
inner join sys.objects so on sic.object_id = so.object_id
inner join sys.sysindexes I ON So.OBJECT_ID = I.ID
Where so.type_desc = 'USER_TABLE' and last_value is not null and indid IN (0,1);
The query needs to get these extra columns:
MaximumValue (IdentityColumn) and MinimumValue (IdentityColumn) for each table.
You should be able to use something along these lines:
DECLARE #cmd NVARCHAR(max);
SET #cmd = '';
SELECT #cmd = #cmd + CASE WHEN (#cmd = '') THEN '' ELSE ' UNION ALL ' END + 'SELECT ''' +
QUOTENAME(s.name) + '.' + QUOTENAME(t.name) + ''' AS TableName, ''' +
QUOTENAME(c.name) + ''' AS ColumnName, MAX(' + QUOTENAME(c.name) + ') AS MaxID, MIN(' +
QUOTENAME(c.name) + ') AS MinID, COALESCE(IDENT_CURRENT(''' + QUOTENAME(s.name) + '.' +
QUOTENAME(t.name) + '''),0) + COALESCE(IDENT_INCR(''' + QUOTENAME(s.name) + '.' +
QUOTENAME(t.name) + '''),0) AS NextValue FROM ' + QUOTENAME(s.name) + '.' + QUOTENAME(t.name)
FROM sys.tables t
INNER JOIN sys.columns c ON t.object_id = c.object_id
INNER JOIN sys.schemas s on t.schema_id = s.schema_id
WHERE c.is_identity = 1
SELECT #cmd; /* Shows the dynamic query generated, not necessary */
EXEC sp_executesql #cmd;
The query uses dynamic SQL to construct a UNION query that gathers the Table Name, Column Name, and Min and Max ID values currently in every table that has an IDENTITY field.
You could quite easily modify this to show the columns in the format you want, along with the other columns you mention in your question.
I've edited the query above to include the "NextValue" field, however I agree with #AaronBertrand in that this value is of little use, since in a busy system it will most certainly be wrong immediately (or shortly thereafter) once the query executes.

How Can I Find All Columns That Contain A String and Null Those Values

My goal is to write a SQL Server script (2008 R2 if it matters) that nulls out all values in all tables where the column name contains "Qualifiers".
E.g. Table A contains columns named "TemperatureQualifiers" and "SalinityQualifiers". For all rows in that table, those values should be set to null. There are also several other tables that have columns with similar names.
This will generate the update statements for you. You can extend this to execute them as dynamic SQL or simply cut/paste the results to another SSMS query window and run them.
select 'update [' + s.name + '].[' + t.name + '] set [' + c.name + '] = NULL'
from sys.columns c
inner join sys.tables t
on c.object_id = t.object_id
inner join sys.schemas s
on t.schema_id = s.schema_id
where c.name like '%Qualifiers%'
and t.type = 'U'
Bit late on this one. This will generate a script that consolidates updates where there are multiple columns in the same table to be updated.
DECLARE #Script nvarchar(MAX);
SET #Script = '';
WITH Cols AS
( SELECT c.object_id,
c.name,
schema_name(t.schema_id) AS SchemaName,
t.name AS TableName
FROM sys.columns c INNER JOIN
sys.tables t ON c.object_id = t.object_id
WHERE c.name LIKE '%Qualifiers%'
AND is_computed=0
AND is_rowguidcol=0
AND is_identity=0
AND is_nullable=1
AND objectproperty(c.object_id, N'IsUserTable')=1
)
,
Tables AS
( SELECT DISTINCT object_id, TableName, SchemaName
FROM Cols
)
,
Statements AS
( SELECT 'UPDATE ' + QUOTENAME(SchemaName) + '.' + QUOTENAME(TableName) + ' SET ' + STUFF(
( SELECT ',' + c.name + '=NULL'
FROM Cols c
WHERE c.object_id = t.object_id FOR XML PATH('')
)
, 1, 1, '') AS Statement
FROM Tables t
)
SELECT #Script = #Script + '
' +Statement
FROM Statements
SELECT #Script AS [processing-instruction(x)] FOR XML PATH('')

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