How to get the columns from SYS.ALL_COLUMNS and use it in COALESCE() Function.

Question

Hi,
I have table called Employe. And the Columns are Emp_ID,EMP_NAME,SRC_SYS_CD,DOB
I have Query like
Select
COALESCE(MAX(CASE WHEN src_sys_cd='1' THEN Emp_id END), MAX(CASE WHEN src_sys_cd='2' THEN Emp_Id END))Emp_Id,
COALESCE(MAX(CASE WHEN src_sys_cd='1' THEN Emp_name END), MAX(CASE WHEN src_sys_cd='2' THEN Emp_Name END))Emp_name,
COALESCE(MAX(CASE WHEN src_sys_cd='1' THEN dob END), MAX(CASE WHEN src_sys_cd='2' THEN dob END))dob ,
from Employe
group by dob.
I want to generalize the query like get the columns from SYS.ALL_COLUMNS table for that table name and want to pass it to COALEACE() function. I tried with Cursor. But i didnt get the appropriate results.
Is there any way to achieve this? Please help me out in this regard.
Thanks,

Answer 1

Is this the kinda thing you're after?
Add a filter to the queries to get just a single table/
WITH allCols AS (
SELECT s.name as sName, o.name AS oName, c.name AS cName, column_id,
CASE WHEN st.name in ('float','bigint','tinyint','int','smallint','bit','datetime','money','date','datetime2','uniqueidentifier','sysname','geography','geometry') THEN st.name
WHEN st.name in ('numeric','real') THEN st.name + '('+CAST(c.scale AS VARCHAR)+','+CAST(c.precision AS VARCHAR)+')'
WHEN st.name in ('varbinary','varchar','binary','char','nchar','nvarchar') THEN st.name + '(' + CAST(ABS(c.max_length) AS VARCHAR) + ')'
ELSE st.name + ' unknown '
END + ' '+
CASE WHEN c.is_identity = 1 THEN 'IDENTITY ' ELSE '' END +
CASE WHEN c.is_nullable = 0 THEN 'NOT ' ELSE '' END + 'NULL' AS bText,
f.name AS fileGroupName
FROM sys.columns c
INNER JOIN sys.objects o
ON c.object_id = o.object_id
AND o.type = 'U'
INNER JOIN sys.systypes st
ON c.user_type_id = st.xusertype
INNER JOIN sys.schemas s
ON o.schema_id = s.schema_id
INNER JOIN sys.indexes i
ON o.object_id = i.object_id
AND i.index_id = (SELECT MIN(index_id) FROM sys.indexes WHERE object_ID = o.object_id)
INNER JOIN sys.filegroups f
ON i.data_space_id = f.data_space_id
), rCTE AS (
SELECT sName, oName, cName, column_id, CAST(cName + ' ' + bText AS VARCHAR(MAX)) as bText, CAST(cName AS VARCHAR(MAX)) AS colList, fileGroupName
FROM allCols
WHERE column_id = 1
UNION ALL
SELECT r.sName, r.oName, r.cName, c.column_id, CAST(r.bText +', ' + c.cName + ' ' +c.bText AS VARCHAR(MAX)), CAST(r.colList+ ', ' +c.cName AS VARCHAR(MAX)), c.fileGroupName
FROM allCols c
INNER JOIN rCTE r
ON c.oName = r.oName
AND c.column_id - 1 = r.column_id
), allIndx AS (
SELECT 'CREATE '+CASE WHEN is_unique = 1 THEN ' UNIQUE ' ELSE '' END+i.type_desc+' INDEX ['+i.name+'] ON ['+CAST(s.name COLLATE DATABASE_DEFAULT AS NVARCHAR )+'].['+o.name+'] (' as prefix,
CASE WHEN is_included_column = 0 THEN '['+c.name+'] '+CASE WHEN ic.is_descending_key = 1 THEN 'DESC' ELSE 'ASC' END END As cols,
CASE WHEN is_included_column = 1 THEN '['+c.name+']'END As incCols,
') WITH ('+
CASE WHEN is_padded = 0 THEN 'PAD_INDEX = OFF,' ELSE 'PAD_INDEX = ON,' END+
CASE WHEN ignore_dup_key = 0 THEN 'IGNORE_DUP_KEY = OFF,' ELSE 'IGNORE_DUP_KEY = ON,' END+
CASE WHEN allow_row_locks = 0 THEN 'ALLOW_ROW_LOCKS = OFF,' ELSE 'ALLOW_ROW_LOCKS = ON,' END+
CASE WHEN allow_page_locks = 0 THEN 'ALLOW_PAGE_LOCKS = OFF' ELSE 'ALLOW_PAGE_LOCKS = ON' END+
')' as suffix, index_column_id, key_ordinal, f.name as fileGroupName
FROM sys.indexes i
LEFT OUTER JOIN sys.index_columns ic
ON i.object_id = ic.object_id
AND i.index_id = ic.index_id
LEFT OUTER JOIN sys.columns c
ON ic.object_id = c.object_id
AND ic.column_id = c.column_id
INNER JOIN sys.objects o
ON i.object_id = o.object_id
AND o.type = 'U'
AND i.type <> 0
INNER JOIN sys.schemas s
ON o.schema_id = s.schema_id
INNER JOIN sys.filegroups f
ON i.data_space_id = f.data_space_id
), idxrCTE AS (
SELECT r.prefix, CAST(r.cols AS NVARCHAR(MAX)) AS cols, CAST(r.incCols AS NVARCHAR(MAX)) AS incCols, r.suffix, r.index_column_id, r.key_ordinal, fileGroupName
FROM allIndx r
WHERE index_column_id = 1
UNION ALL
SELECT o.prefix, COALESCE(r.cols,'') + COALESCE(', '+o.cols,''), COALESCE(r.incCols+', ','') + o.incCols, o.suffix, o.index_column_id, o.key_ordinal, o.fileGroupName
FROM allIndx o
INNER JOIN idxrCTE r
ON o.prefix = r.prefix
AND o.index_column_id - 1 = r.index_column_id
SELECT 'CREATE TABLE ['+sName+'].[' + oName + '] ('+bText+') ON [' + fileGroupName +']'
FROM rCTE r
WHERE column_id = (SELECT MAX(column_id) FROM rCTE WHERE r.oName = oName)
UNION ALL
SELECT prefix + cols + CASE WHEN incCols IS NOT NULL THEN ') INCLUDE ('+incCols ELSE '' END + suffix+' ON [' + fileGroupName +']'
FROM idxrCTE x
WHERE index_column_id = (SELECT MAX(index_column_id) FROM idxrCTE WHERE x.prefix = prefix)