How to Find the Most Recent Date Across Multiple Date Columns in SQL?
SQL multi-column date maximum value acquisition skills
When working with tables containing multiple date or timestamp columns, you need to identify the latest value for each row. This article provides a SQL solution for getting the maximum value in multiple columns, converting raw data into a more manageable format.
Problem Description
Suppose there is a table called "TableName" with the following columns: [Number], [Date1], [Date2], [Date3], and [Cost]. The goal is to convert this table into a new table that displays the following information for each row: [Number], [Most_Recent_Date], and [Cost].
Solution
In SQL Server, an effective way to get the maximum value of multiple columns is to use T-SQL and SQL Server syntax:
SELECT [Other Fields], (SELECT Max(v) FROM (VALUES (date1), (date2), (date3),...) AS value(v)) as [MaxDate] FROM [YourTableName]
This code uses the table value constructor "VALUES" to build a temporary table that contains the values of the individual columns in the original table. The SELECT statement in parentheses calculates the maximum value of each row and assigns it to the alias "[MaxDate]". By combining this information with other fields from the original table, we get a new table with the desired output format.
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