How to check which columns in my database hold data dynamically - sql-server

Question

I am dealing with a problem that I need to make a sql query like this:
SELECT
SUM(CASE WHEN ID IS NOT NULL THEN 0 ELSE 1 END) AS column_ID_count,
SUM(CASE WHEN NAME IS NOT NULL THEN 0 ELSE 1 END) AS column_NAME_count,
SUM(CASE WHEN COMMENT IS NOT NULL THEN 1 ELSE 0 END) AS column_COMMENT_count
FROM
Table1
The problem is that I have more than 100 columns so making this query by hand will be a real pain. So I was thinking that there should be a way to select all column names and dump them to text file. The output would look like:
SUM(CASE WHEN NAME IS NOT NULL THEN 0 ELSE 1 END) AS column_NAME_count,
...
SUM(CASE WHEN COMMENT IS NOT NULL THEN 1 ELSE 0 END) AS column_COMMENT_count
I tried exec sp_help but that is not what I need. So is there a way to do this with a query?

Answer 1

This will give you column names for the table in question.
SELECT COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'yourtablename'

Answer 2

If you want a list of all column names in your table then you want something like this;
DECLARE #TableName varchar(50); SET #TableName = 'TableName'
SELECT c.name
INTO #ColumnNames
FROM sys.columns c
JOIN sys.objects o
ON c.object_id = o.object_id
WHERE o.name = #TableName
SELECT * FROM #ColumnNames
Drop the results to a text file if that's what you want and you're done.
If you want a script to return all columns in your database and whether they contain data, you could use this;
SELECT 'SELECT count([' + c.name + ']) as Data_Count, ''' + o.name + '.' + c.name + ''' AS Table_Column FROM [' + o.name + '] UNION ALL '
FROM sys.columns c
JOIN sys.objects o
ON c.object_id = o.object_id
WHERE c.is_nullable = 1
AND o.type = 'U'
And paste the results into a new window. You'll have to remove the final UNION ALL and this won't work with text or ntext data types so if you have some of these you'll have to remove them. You could filter them out in the query but then you'd never know about them.
Edit: If you want to exclude the incompatible data types then use this query;
SELECT 'SELECT count([' + c.name + ']) as Data_Count, ''' + o.name + '.' + c.name + ''' AS Table_Column FROM [' + o.name + '] UNION ALL '
FROM sys.columns c
JOIN sys.objects o
ON c.object_id = o.object_id
JOIN sys.types t
ON c.user_type_id = t.user_type_id
WHERE c.is_nullable = 1
AND o.type = 'U'
AND t.name NOT IN ('image','text','ntext')
Just remember to check these data types with a different query so you don't miss them.

Answer 3

try this query
declare #cnmae nvarchar(max)='select '
SELECT #cnmae+= 'sum( case when ' + COLUMN_NAME +
' is not null then 0 else 1 end) as column_'+COLUMN_NAME+'_count,'
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'Table1'
select #cnmae=stuff(#cnmae,len(#cnmae),1,'') + ' from Table1'
exec sp_executesql #cnmae