How do I compare two columns in the same table?

Question

I would like to compare two columns in the same table. I want to be able to return all rows where the two columns have the same value. I am looking for something like `SELECT * FROM FOO WHERE C1 = C4`. Therefore in the example below I would return only the first row: ``` C1 || C2 || C3 || C4 -------------------------- 1 || a || b || 1 2 || a || b || 4 3 || b || d || 2 4 || b || d || 2 ``` If it matters, I am using `SQLite` (more specifically `WebSQL`).

Accepted Answer

`SELECT * FROM FOO WHERE C1 = C4` should work. Does it not?

If not, are they the same data type and length? You may need to convert.

I don't know about WebSql, but I've seen some db systems that refuse to match if one is a varchar(5) and the other is a varchar(10) even though they hold the same value. In those systems you have to use something like

```
 Convert(varchar, 10, FieldName)
```

to get a match.

How do I compare two columns in the same table?

Solution

Problem