Question: I am developing site using PHP and backend ClickHouse database. When i using like queries , it is not supporting case-sensitive words. 

```
select id,comments from discussion where  comments LIKE "%Data not reflect%";

```

Is there any way to search case-insensitive words?

Answer: 
Case insensitive **ILIKE** operator was added to CH starting with [version 20.6.3.28](https://clickhouse.tech/docs/en/whats-new/changelog/#clickhouse-release-v20-6-3-28-stable):

```sql
SELECT *
FROM
(
    SELECT '** Data not reflect **' AS text
    UNION ALL
    SELECT '** data not reflect **'
)
WHERE text ILIKE '%Data not reflect%'

/*
┌─text───────────────────┐
│ ** Data not reflect ** │
│ ** data not reflect ** │
└────────────────────────┘
*/

```
Use `positionCaseInsensitive` or `positionCaseInsensitiveUTF8`

Just like that 

```
SELECT id,comments
FROM discussion
WHERE positionCaseInsensitive(comments,'Data not reflect')>0;

```

For more complicated patterns you can use regular expression with `i` flag inside: 

```
SELECT ... WHERE match(comment, '(?i)Data.*not reflect');

```

See documentation: <https://clickhouse.yandex/docs/en/query_language/functions/string_search_functions/#position-haystack-needle-locate-haystack-needle>