T-SQL: join columns & indicate type i other column

Question

Closed. This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 6 days ago. Improve this question I have a table with 6 columns : c1_x_base c2_y_base c3_x_first c4_y_first c5_x_second c6_y_second Now I would like to get to: x y type with as types: "base", "first" & "second. I am lost on how to make this happen in the most performant way in T-SQL. JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

SELECT CASE X.Category WHEN 'Base' THEN c1_x_base WHEN 'First' THEN c3_x_first WHEN 'Second' THEN c5_x_second END AS X ,CASE X.Category WHEN 'Base' THEN c2_y_base WHEN 'First' THEN c4_y_first WHEN 'Second' THEN c6_y_second END AS Y ,X.Category FROM YourTable T CROSS APPLY ( VALUES ('Base'), ('First'), ('Second') ) X (Category);