Knex js How to apply union on 2 tables which has different number of columns

I have 2 tables with diff columns as shown below

  • Table - A Columns

Name, Age, Gender, email_id

  • Table -B Columns

course, course_type, university

  • How to convert below mentioned query in Knexjs

SELECT NAME, EMAIL_ID, NULL AS COURSE, NULL AS UNIVERSITY FROM TABLEA UNION SELECT NULL AS NAME, NULL AS EMAILID, COURSE, UNIVERSITY FROM TABLEB

1 answer

  • answered 2022-05-03 10:02 user2710786

    I tried below mentioned knex js query but getting error

    • Knexjs query

    myDB .select('NAME', 'EMAIL_ID', {'NULL':'COURSE'}, {'NULL':'UNIVERSITY'}) .from('TABLEA') .union(canonDB.select({'NULL':'NAME'},{'NULL':'EMAILID'}, COURSE',UNIVERSITY}).from('TABLEB'))

    • Error :

    Unknown column 'NULL' in 'field list'

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