Loop through multiple Float columns in a DB using Dynamic SQL - sql

Question

How do I loop through multiple columns from different tables in a database?. I am finding the result I need by querying one column at a time which takes lot of time.
SELECT MAX
(CASE Charindex('.', COLUMN1)
WHEN 0 THEN 0
ELSE
Len (Cast(Cast(Reverse(CONVERT(VARCHAR(50), COLUMN1, 128)
) AS FLOAT) AS BIGINT))
END) AS MAX_LENGTH
FROM DB1.dbo.TABLE1
My code is here but it won't work because I am sending more than one value
DECLARE #cols NVARCHAR(MAX)
,#sql NVARCHAR(MAX)
SET #cols = (SELECT quotename(COLUMN_NAME) FROM BRSDATA.INFORMATION_SCHEMA.COLUMNS A
inner join BRSDATA.INFORMATION_SCHEMA.TABLES B
on A.TABLE_NAME = B.TABLE_NAME
where TABLE_TYPE = 'BASE TABLE'
and DATA_TYPE = 'Float')
Set #sql = 'SELECT MAX(CASE Charindex(''.'',' + #cols + ')
WHEN 0 THEN 0
ELSE
Len (Cast(Cast(Reverse(CONVERT(VARCHAR(50), ' + #cols + ', 128)
) AS FLOAT) AS BIGINT))
END) AS MAX_LENGTH'
print(#sql)
Msg 512, Level 16, State 1, Line 101
Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.
I also tried using a cursor and the 'query executed successfully' but I don't see the results even when not closing and deallocating the cursor.
DECLARE #SchemaName SYSNAME = 'dbo'
DECLARE #TableName SYSNAME
DECLARE #ColumnName SYSNAME
DECLARE FLOAT_COLUMNS CURSOR FOR
SELECT t.name,c.name
FROM BRSDATA.sys.tables AS t
INNER JOIN BRSDATA.sys.schemas AS s
ON t.[schema_id] = s.[schema_id]
inner join BRSDATA.sys.columns AS c
on c.object_id = t.object_id
WHERE s.name = 'dbo'
and type_desc = 'USER_TABLE';
OPEN FLOAT_COLUMNS
FETCH NEXT FROM FLOAT_COLUMNS
INTO #TableName, #ColumnName
WHILE ##FETCH_STATUS = 0
BEGIN
DECLARE #Columns NVARCHAR(MAX)
SET #Columns =
STUFF(
(SELECT
',' + QUOTENAME(name)
FROM
sys.columns
WHERE
object_id = OBJECT_ID(QUOTENAME(#TableName) + '.' + QUOTENAME(#ColumnName))
FOR XML PATH(''))
,1,1,'')
DECLARE #SQL AS NVARCHAR(MAX)
SET #SQL = 'SELECT' + QUOTENAME(#TableName) + ',' + QUOTENAME(#ColumnName) + ', MAX(CASE Charindex(''.'',' + #Columns + ')
WHEN 0 THEN 0
ELSE
Len (Cast(Cast(Reverse(CONVERT(VARCHAR(50), ' + #Columns + ', 128)
) AS FLOAT) AS BIGINT))
END) AS MAX_LENGTH'
--use print to view and copy your dynamic sql string to see if you have formed it correctly
PRINT #SQL
--EXECUTE (#SQL)
FETCH NEXT FROM FLOAT_COLUMNS
INTO #TableName, #ColumnName
END
CLOSE FLOAT_COLUMNS
DEALLOCATE FLOAT_COLUMNS

Answer 1

not sure if this is what you need,but this is how i would do it:
DECLARE #cols NVARCHAR(MAX)
,#table NVARCHAR(MAX)
,#sql NVARCHAR(MAX)
,#X INT = 1
WHILE #X < (
SELECT MAX(ROWID) FROM
(
SELECT quotename(COLUMN_NAME) col
,ROW_NUMBER()over(ORDER BY COLUMN_NAME) ROWID
FROM INFORMATION_SCHEMA.COLUMNS A
inner join INFORMATION_SCHEMA.TABLES B
on A.TABLE_NAME = B.TABLE_NAME
where TABLE_TYPE = 'BASE TABLE'
and DATA_TYPE = 'Float'
) AS X
WHERE ROWID < 10
)
BEGIN
SET #cols =
(SELECT col FROM
(
SELECT quotename(COLUMN_NAME) col
,ROW_NUMBER()over(ORDER BY COLUMN_NAME) ROWID
FROM INFORMATION_SCHEMA.COLUMNS A
inner join INFORMATION_SCHEMA.TABLES B
on A.TABLE_NAME = B.TABLE_NAME
where TABLE_TYPE = 'BASE TABLE'
and DATA_TYPE = 'Float'
) AS X
WHERE ROWID = #X
)
SET #table =
(SELECT tablename FROM
(
SELECT quotename(A.TABLE_NAME) tablename
,ROW_NUMBER()over(ORDER BY COLUMN_NAME) ROWID
FROM INFORMATION_SCHEMA.COLUMNS A
inner join INFORMATION_SCHEMA.TABLES B
on A.TABLE_NAME = B.TABLE_NAME
where TABLE_TYPE = 'BASE TABLE'
and DATA_TYPE = 'Float'
) AS X
WHERE ROWID = #X
)
Set #sql = 'SELECT MAX(CASE Charindex(''.'',' + #cols + ')
WHEN 0 THEN 0
ELSE
Len (Cast(Cast(Reverse(CONVERT(VARCHAR(50), ' + #cols + ', 128)
) AS FLOAT) AS BIGINT))
END) AS MAX_LENGTH
,MAX(CASE Charindex(''.'',' + #table + ')
WHEN 0 THEN 0
ELSE
Len (Cast(Cast(Reverse(CONVERT(VARCHAR(50), ' + #table + ', 128)
) AS FLOAT) AS BIGINT))
END) AS MAX_LENGTH'
PRINT(#sql)
SET #X = #X +1
END

Answer 2

I believe this script can help you :
DECLARE #Query TABLE (SchemaName VARCHAR(100)
,TableName VARCHAR(100)
,ColumnName VARCHAR(1000)
)
INSERT INTO #Query
SELECT A.TABLE_SCHEMA,A.TABLE_NAME,' MAX(CASE Charindex(''.'',' + QUOTENAME(COLUMN_NAME) + ')
WHEN 0 THEN 0
ELSE Len (Cast(Cast(Reverse(CONVERT(VARCHAR(50), ' + QUOTENAME(COLUMN_NAME) + ', 128) ) AS FLOAT) AS BIGINT))
END) AS ['+COLUMN_NAME+'_MAX_LENGTH]'
FROM INFORMATION_SCHEMA.COLUMNS A
INNER JOIN INFORMATION_SCHEMA.TABLES B
ON A.TABLE_NAME = B.TABLE_NAME
WHERE TABLE_TYPE = 'BASE TABLE'
AND DATA_TYPE = 'FLOAT'
SELECT 'SELECT '+
STUFF((
SELECT ',' + ColumnName
FROM #Query Q2
WHERE Q1.SchemaName=q2.SchemaName AND Q1.TableName=q2.TableName
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
, 1, 2, '')
+' FROM '+Q1.SchemaName+'.'+Q1.TableName
FROM
(SELECT DISTINCT SchemaName,TableName FROM #Query) Q1

Answer 3

use BRSDATA;
begin try drop table #temp end try begin catch end catch ;
DECLARE #TableName nvarchar(250);
DECLARE #ColumnName nvarchar(250);
declare #x int;
DECLARE #FLOATV as float = 3.141592653;--searching for this in all float vals in all tables
SELECT t.name,c.name colname
into #temp
FROM sys.tables AS t
INNER JOIN sys.schemas AS s
ON t.[schema_id] = s.[schema_id]
inner join sys.columns AS c
on c.object_id = t.object_id
WHERE s.name = 'dbo'
and type_desc = 'USER_TABLE'
and exists(select * from sys.types where name = 'float' and system_type_id = c.system_type_id);
SET Nocount on;
DECLARE FLOAT_TAB CURSOR FOR
SELECT DISTINCT [name] from #temp;
OPEN FLOAT_TAB;
FETCH NEXT FROM FLOAT_TAB
INTO #TableName;
WHILE ##FETCH_STATUS = 0
BEGIN
DECLARE #SQL nvarchar(max) = '';
DECLARE #COND nvarchar(max) = '';
SET #SQL = 'SELECT ';
DECLARE COL_TAB CURSOR FOR
SELECT colname from #temp where name = #TableName;
OPEN COL_TAB;
FETCH NEXT FROM COL_TAB
INTO #ColumnName;
WHILE ##FETCH_STATUS = 0
BEGIN
SET #SQL = #SQL + ' ' + #ColumnName + ',';
SET #COND = #COND + #ColumnName + ' = ' + cast(#floatv as nvarchar(60)) + ' OR ' ;
FETCH NEXT FROM col_tab INTO #ColumnName
END
SET #SQL = LEFT(#SQL, len(#sql) - 1) + ' FROM ' + #TableName + ' WHERE ' + LEFT(#COND, LEN(#COND) - 3);
print #sql;
EXECUTE ( #SQL);
close col_tab;
deallocate col_tab;
--waitfor delay '00:05';
FETCH NEXT FROM FLOAT_TAB into #tablename;
END
close float_tab
deallocate float_tab;