SQL
Using Collations
In the stand-alone installation of DuckDB three collations are included: `NOCASE`, `NOACCENT` and `NFC`. The `NOCASE` collation compares characters as equal regardless of their casing. The `NOACCENT` collation compares characters as equal regardless of their accents. The `NFC` collation performs NFC-normalized comparisons, see [Unicode normalization](https://en.wikipedia.org/wiki/Unicode_equivalence#Normalization) for more information.  
```sql
SELECT 'hello' = 'hElLO';
```  
```text
false
```  
```sql
SELECT 'hello' COLLATE NOCASE = 'hElLO';
```  
```text
true
```  
```sql
SELECT 'hello' = 'hëllo';
```  
```text
false
```  
```sql
SELECT 'hello' COLLATE NOACCENT = 'hëllo';
```  
```text
true
```  
Collations can be combined by chaining them using the dot operator. Note, however, that not all collations can be combined together. In general, the `NOCASE` collation can be combined with any other collator, but most other collations cannot be combined.  
```sql
SELECT 'hello' COLLATE NOCASE = 'hElLÖ';
```  
```text
false
```  
```sql
SELECT 'hello' COLLATE NOACCENT = 'hElLÖ';
```  
```text
false
```  
```sql
SELECT 'hello' COLLATE NOCASE.NOACCENT = 'hElLÖ';
```  
```text
true
```