Check Equality of Two Columns

Check Equality of Two Columns

Situation: There are two tables with two columns with different names. You want a simple script to check if the rows of those columns are equal, so the two tables can be joined.

Here’s the SQL script, taken from this stackoverflow answer.

SELECT 
  CASE WHEN COLUMN1 = COLUMN2 
    THEN '1' 
    ELSE '0' 
  END 
  AS MyDesiredResult
FROM Table1
INNER JOIN Table2 ON Table1.PrimaryKey = Table2.ForeignKey

Here’s an application of this script used in DAO Dash. We are comparing two tables - discord_user and discord_messages by these two columns respectively:

1. discord_user_id
2. author_user_id

SELECT 
  CASE WHEN discord_user_id = author_user_id 
    THEN '1'
    ELSE '0'
  END
  AS AreColumnsEqual
FROM discord_user d
INNER JOIN discord_messages m ON d.discord_user_id = m.author_user_id 

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