edgar2020 commented on code in PR #16862:
URL: https://github.com/apache/druid/pull/16862#discussion_r1711848826
##########
docs/querying/sql-functions.md:
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@@ -1341,28 +1427,90 @@ Returns the rank with gaps for a row within a window.
For example, if two rows t
## REGEXP_EXTRACT
-`REGEXP_EXTRACT(<CHARACTER>, <CHARACTER>, [<INTEGER>])`
+Apply regular expression `pattern` to `expr` and extract the `N`-th capture
group. If `N` is unspecified or zero, returns the first substring that matches
the pattern. Returns `null` if there is no matching pattern.
-**Function type:** [Scalar, string](sql-scalar.md#string-functions)
+* **Syntax:** `REGEXP_EXTRACT(expr, pattern[, N])`
+* **Function type:** Scalar, string
+
+<details><summary>Example</summary>
+
+The following example uses regular expressions to find city names inside the
`OriginCityName` column from the `flight-carriers` datasource by matching what
comes before the comma.
+
+```sql
+SELECT
+ "OriginCityName" AS "original_expr",
+ REGEXP_EXTRACT("OriginCityName", '([^,]+)', 0) AS "pattern_extracted"
+FROM "flight-carriers"
+LIMIT 1
+```
+
+Returns the following:
+
+| `original_expr` | `pattern_extracted` |
+| -- | -- |
+| `San Juan, PR` | `San Juan`|
+
+</details>
-Applies a regular expression to the string expression and returns the _n_th
match.
+[Learn more](sql-scalar.md#string-functions)
## REGEXP_LIKE
-`REGEXP_LIKE(<CHARACTER>, <CHARACTER>)`
+Returns `true` if the regular expression `pattern` finds a match in `expr`.
Returns `false` otherwise.
-**Function type:** [Scalar, string](sql-scalar.md#string-functions)
+* **Syntax:** `REGEXP_LIKE(expr, pattern)`
+* **Function type:** Scalar, string
+
+<details><summary>Example</summary>
+
+The following example returns `true` when the `OriginCityName` column from
`flight-carriers` has a city name with two words.
Review Comment:
Yeah I think yours is more accurate, but what about "city name with a space
in the name"?
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