I have an Accounts table with columns name, password and email . They are

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Asked: May 22, 20262026-05-22T00:42:14+00:00 2026-05-22T00:42:14+00:00

I have an Accounts table with columns name, password and email. They are all type nvarchar.
I wrote a query like

SELECT name, password, ISNULL(email, 'eeee') 
FROM Accounts 
WHERE name = '" + textBox1.Text + "' AND password ='" + textBox2.Text + "'"

I read the email as reader.getString(2) since it is nvarchar.

As I read from the internet, if email is NULL, then it should return eeee. But it says System.boolean can not be translated to System.String.

How can I correct this? Why does it return a boolean value?

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Editorial Team · Answer 1 · 2026-05-22T00:42:14+00:00

Editorial Team

According this ISNULL is not implemented in SQL Server CE. I would expect to see a syntax error raised, however.

Workaround: you can use CASE WHEN email IS NULL THEN 'eeee' ELSE email END or COALESCE. Preferably the latter.

Also use parameterised queries. If you don’t know why you should, learn.

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