INSERT INTO #ExpressionToDataTypeAndNull
( DATA_TYPE ,
IS_NULLABLE ,
CustomExpression
)
VALUES 
( 'varchar','YES','LTRIM(RTRIM(ISNULL("<column>",'''')))')
,( 'varchar','NO','LTRIM(RTRIM("<column>"))"')
,( 'nvarchar','YES','LTRIM(RTRIM(ISNULL("<column>",'''')))')
,( 'nvarchar','NO','LTRIM(RTRIM("<column>"))')
,( 'datetime','YES','CAST("<column>" AS varchar(max))')
,( 'datetime','NO','CAST("<column>" AS varchar(max))')
;

DECLARE @TableName nvarchar(128)
SET @TableName = 'FictionalEmployees'

DECLARE @SqlSelect NVARCHAR(MAX)

SELECT @SqlSelect = COALESCE(
	@SqlSelect + ', ' + ISNULL(REPLACE(CustomExpression,'<column>', COLUMN_NAME), COLUMN_NAME )
	, ISNULL(REPLACE(CustomExpression,'<column>', COLUMN_NAME), COLUMN_NAME )
	) + ' AS "' + COLUMN_NAME + '"'
FROM INFORMATION_SCHEMA.COLUMNS a
FULL OUTER JOIN #ExpressionToDataTypeAndNull b
ON a.DATA_TYPE = b.DATA_TYPE
AND a.IS_NULLABLE = b.IS_NULLABLE
WHERE TABLE_NAME = @TableName
ORDER BY ordinal_position ASC;


SET @SqlSelect = 'SELECT ' + @SqlSelect + 'FROM ' + @TableName
PRINT @SqlSelect
-- EXECUTE sp_executesql @SqlSelect

CREATE TABLE #ExpressionToDataTypeAndNull
(
	DATA_TYPE			VARCHAR(15),
	IS_NULLABLE			VARCHAR(3) ,
	CustomExpression		VARCHAR(128)
)

INSERT INTO #ExpressionToDataTypeAndNull( DATA_TYPE , IS_NULLABLE , CustomExpression )
VALUES ( 'varchar','YES','LTRIM(RTRIM(ISNULL("<column>",''''))) AS "<column>"')

INSERT INTO #ExpressionToDataTypeAndNull( DATA_TYPE , IS_NULLABLE , CustomExpression )
VALUES ( 'varchar','NO','LTRIM(RTRIM("<column>")) AS "<column>"')

INSERT INTO #ExpressionToDataTypeAndNull( DATA_TYPE , IS_NULLABLE , CustomExpression )
VALUES ( 'nvarchar','YES','LTRIM(RTRIM(ISNULL("<column>",''''))) AS "<column>"')

INSERT INTO #ExpressionToDataTypeAndNull( DATA_TYPE , IS_NULLABLE , CustomExpression )
VALUES ( 'nvarchar','NO','LTRIM(RTRIM("<column>")) AS "<column>"')

INSERT INTO #ExpressionToDataTypeAndNull( DATA_TYPE , IS_NULLABLE , CustomExpression )
VALUES ( 'datetime','YES','CAST("<column>" AS varchar(max)) AS "<column>"')

INSERT INTO #ExpressionToDataTypeAndNull( DATA_TYPE , IS_NULLABLE , CustomExpression )
VALUES ( 'datetime','NO','CAST("<column>" AS varchar(max)) AS "<column>"')

DECLARE @TableName VARCHAR(128)
SET @TableName = 'EntityRelationshipCache'

DECLARE @SqlSelect NVARCHAR(MAX)

SELECT @SqlSelect = COALESCE( @SqlSelect + ', ' + ISNULL(REPLACE(CustomExpression,'<column>', COLUMN_NAME), COLUMN_NAME )
        , ISNULL(REPLACE(CustomExpression,'<column>', COLUMN_NAME), COLUMN_NAME ) )
FROM INFORMATION_SCHEMA.COLUMNS a
FULL OUTER JOIN #ExpressionToDataTypeAndNull b
ON a.DATA_TYPE = b.DATA_TYPE
AND a.IS_NULLABLE = b.IS_NULLABLE
WHERE TABLE_NAME = @TableName
ORDER BY ordinal_position ASC;

SET @SqlSelect = 'SELECT ' + REPLACE( @SqlSelect, '"', '') + ' FROM ' + @TableName

PRINT @SqlSelect

--EXECUTE ( @SqlSelect )

IF ( OBJECT_ID( 'TEMPDB..#ExpressionToDataTypeAndNull' ) IS NOT NULL )
BEGIN
	DROP TABLE #ExpressionToDataTypeAndNull
END