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Like a book or a beautiful picture, we also need to take care with how we write a query. We can either use SQLA or Teradata Studio Express for this purpose. The main thing is, our query should be readable and should easily be understood.

• Keep individual SQL statements small as they are easier to debug and support. 
• Always qualify table names with database names; default database assignments can change. 
• Use ANSI join syntax with join criteria in the ON clause, not in the WHERE clause. Join the clause on one line, tableA inner join tableB, and use a separate line for each criteria.
• Use a separate line for each table in the form list.
• When using subqueries, indent the subqueries and ensure the parenthesis are aligned.
• If any third-party tool is used to generate the query, remove the additional formatting that comes along with it.
• Change keyword shortcuts (sel, ins, upd, ct, and so on) to their full word equivalents (SELECT, INSERT, UPDATE, CREATE TABLE, and so on).
• Use tabs and spaces to build a block structure where each item of a clause begins in the same column. 
• Include an inline comment for any hard coded values. The proper use of the block comment /**COMMENT USE**/:

/** Query to get employee name and invoice sum**/
SELECT  oc.Employee_name 
 , r.WEEK_YEAR 
  , sum(oc.INVOICE)  Invc_Sum 
 FROM  Test01.ORGANIZATION  oc INNER JOIN SALES.RETAIL_INVOICE_AGG  r
  AND  oc.start_dt = r.repo_dt 
 WHERE  oc.Dept_no =  'RETAIL'

These are some tips that can be used to maintain the integrity of the SQL codes and make them more readable.