Category Archives: Reporting

How to find columns from all Tables of a Database

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If your job is to create reports using SQL chances are you have or will encounter this situation:

You’ve been asked to prepare a report, but the person who has asked for the report simply has a list of fields they want and they have no idea where those fields come from. They may have received previous reports in the past, so they know the fields exist, but they cannot provide any of the SQL queries used to create these reports as an example.

You, the developer, may not be familiar with that particular area of the business or associated data sources. Possibly because you typically prepared financial reports and this request has come from the operations or marketing departments.

So the first step is to locate these columns within the database.

The following query will return the Table Name, Schema Name and Column Name from the database.

In the example below all instances where the column name equals CustomerID, OrderID, OrderDate will be returned. Also Column names that contain the word Status or Promotion will also be return. Simply change or add additional columns names as needed. 

USE [YourDatabaseName];
GO

SELECT T.NAME AS TableName
	,SCHEMA_NAME(SCHEMA_ID) AS SchemaName
	,C.NAME AS ColumnName
FROM SYS.TABLES AS t
INNER JOIN SYS.COLUMNS C ON T.OBJECT_ID = C.OBJECT_ID
WHERE C.NAME = 'CustomerID'
	OR C.NAME = 'OrderID'
	OR C.NAME = 'OrderDate'
	OR C.NAME LIKE '%Status%'
	OR C.NAME LIKE '%Promotion%'
ORDER BY SchemaName
	,TableName;

 

That should help get you started in preparing the report.

How to get the hour from a datetime string (T-SQL)

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Often data is entered into the database as a string (varchar), when a more appropriate data type should have been applied.

Here’s a snippet of T-SQL for dealing with datetime data, stored as varchar, when what you really need is the hour. 

DECLARE @DateTime AS VARCHAR(25)

-- GET THE CURRENT DATETIME AND CONVERT INTO A STRING
SET @DateTime = (
		SELECT CONVERT(VARCHAR(25), GETDATE(), 120)
		)

--PRINT @DateTime
-- GET HOUR FROM DATETIME AS A STRING
SELECT DATEPART(HOUR, CONVERT(DATETIME, CONVERT(VARCHAR(13), @DateTime, 120) + ':00')) AS ConvertedHour

 

Why would data be stored as a varchar instead of using the appropriate data type in the first place?

The most common reason might be that XML files have been loaded without any data type conversions being applied, i.e. dates have been entered as strings along with everything else.

Why would you need this code?

Should you be confronted with data in this raw string form you would be unable to apply a clause regarding a specific hour. Ideally there should be some sort of staging table to convert the fields into the appropriate data types but if you simply wanted to apply some clauses to select specific data, which will be outputted to an excel file for example, that additional effort may be unnecessary.