Add FAQ section to README

Fixes #114

README.md

@@ -110,7 +110,27 @@ will generate with the Dollar Placeholder:
 SELECT * FROM nodes WHERE meta->'format' ?| array[$1,$2]
 ```
 
+## FAQ
 
+**How can I build an IN query on composite keys / tuples, e.g. `WHERE (col1, col2) IN ((1,2),(3,4))`? ([#104](https://github.com/Masterminds/squirrel/issues/104))**
+
+Squirrel does not explicitly support tuples, but you can get the same effect with e.g.:
+
+```go
+sq.Or{
+  sq.Eq{"col1": 1, "col2": 2},
+  sq.Eq{"col1": 3, "col2": 4}}
+```
+
+```sql
+WHERE (col1 = 1 AND col2 = 2) OR (col1 = 3 AND col2 = 4)
+```
+
+(which should produce the same query plan as the tuple version)
+
+**Why doesn't `Eq{"mynumber": []uint8{1,2,3}}` turn into an `IN` query? ([#114](https://github.com/Masterminds/squirrel/issues/114))**
+
+Values of type `[]byte` are handled specially by `database/sql`. In Go, [`byte` is just an alias of `uint8`](https://golang.org/pkg/builtin/#byte), so there is no way to distinguish `[]uint8` from `[]byte`.
 
 ## License