Question

sqlite3

I have two tables, Table1 and Table2.

Both of these tables have a column called Name.

I would like to query Table2 and return the Name column. In addition, I would like to return a column containing the values 1 or 0 depending on whether any rows in Table1 also contain the same value for Name.

What is the most efficient way to do this?

I’m looking for something like:

SELECT
  Name, IF EXISTS (SELECT * FROM Table1 WHERE Table1.Name = Table2.Name) 1 ELSE 0
FROM
  Table2

Answer 1

Sorry, I’m not very familiar with SQLite, but this should work for you. The trick is a Left Outer Join and comparison on the joined table.

SELECT
    Table2.Name,
    CASE WHEN Table1.Name IS NOT NULL THEN 1 ELSE 0 END
FROM
    Table2
LEFT OUTER JOIN
    Table1 ON Table1.Name = Table2.Name

I’m not so sure the CASE syntax is the best but if you are more familiar with conditionals in SQLite you can clean that part up.