Adding Contains ESQL String function

docs/changelog/133016.yaml

@@ -0,0 +1,5 @@
+pr: 133016
+summary: Adding Contains ESQL String function
+area: ES|QL
+type: feature
+issues: []

docs/reference/query-languages/esql/_snippets/lists/string-functions.md

@@ -1,6 +1,7 @@
 * [`BIT_LENGTH`](../../functions-operators/string-functions.md#esql-bit_length)
 * [`BYTE_LENGTH`](../../functions-operators/string-functions.md#esql-byte_length)
 * [`CONCAT`](../../functions-operators/string-functions.md#esql-concat)
+* [`CONTAINS`](../../functions-operators/string-functions.md#esql-contains)
 * [`ENDS_WITH`](../../functions-operators/string-functions.md#esql-ends_with)
 * [`FROM_BASE64`](../../functions-operators/string-functions.md#esql-from_base64)
 * [`HASH`](../../functions-operators/string-functions.md#esql-hash)

docs/reference/query-languages/esql/functions-operators/string-functions.md

@@ -21,6 +21,9 @@ mapped_pages:
 :::{include} ../_snippets/functions/layout/concat.md
 :::
 
+:::{include} ../_snippets/functions/layout/contains.md
+:::
+
 :::{include} ../_snippets/functions/layout/ends_with.md
 :::
 

x-pack/plugin/esql/qa/testFixtures/src/main/resources/semantic_text.csv-spec

@@ -515,6 +515,21 @@ result:keyword
 <em>live long and prosper</em>
 ;
 
+contains
+required_capability: semantic_text_field_caps
+
+FROM semantic_text METADATA _id
+| EVAL result = contains(semantic_text_field, "all")
+| KEEP _id, result
+| SORT _id
+;
+
+_id:keyword | result:boolean
+1           | false
+2           | true
+3           | false
+;
+
 endsWith
 required_capability: semantic_text_field_caps
 

x-pack/plugin/esql/qa/testFixtures/src/main/resources/string.csv-spec

@@ -388,6 +388,92 @@ emp_no:integer | name:keyword
 10010          | null
 ;
 
+
+contains#[skip:-9.2.99,reason:new string function added in 9.3]
+// tag::contains[]
+ROW a = "hello"
+| EVAL has_ll = CONTAINS(a, "ll")
+// end::contains[]
+;
+
+// tag::contains-result[]
+a:keyword | has_ll:boolean
+hello     | true
+// end::contains-result[]
+;
+
+containsFail#[skip:-9.2.99,reason:new string function added in 9.3]
+row a = "hello" | eval a_ll = contains(a, "int");
+
+a:keyword | a_ll:boolean
+hello | false
+;
+
+containsLongerSubstr#[skip:-9.2.99,reason:new string function added in 9.3]
+row a = "hello" | eval a_ll = contains(a, "farewell");
+
+a:keyword | a_ll:boolean
+hello | false
+;
+
+containsSame#[skip:-9.2.99,reason:new string function added in 9.3]
+row a = "hello" | eval a_ll = contains(a, "hello");
+
+a:keyword | a_ll:boolean
+hello | true
+;
+
+containsWithSubstring#[skip:-9.2.99,reason:new string function added in 9.3]
+from employees | where emp_no <= 10010 | eval f_s = substring(last_name, 2) | eval f_l = contains(last_name, f_s) | keep emp_no, last_name, f_s, f_l;
+ignoreOrder:true
+
+emp_no:integer | last_name:keyword | f_s:keyword | f_l:boolean
+10001 | Facello   | acello | true
+10002 | Simmel    | immel | true
+10003 | Bamford   | amford | true
+10004 | Koblick   | oblick | true
+10005 | Maliniak  | aliniak | true
+10006 | Preusig   | reusig | true
+10007 | Zielinski | ielinski | true
+10008 | Kalloufi  | alloufi | true
+10009 | Peac      | eac | true
+10010 | Piveteau  | iveteau | true
+;
+
+containsUtf16Emoji#[skip:-9.2.99,reason:new string function added in 9.3]
+row a = "🐱Meow!🐶Woof!" | eval f_s = substring(a, 2) | eval f_l = contains(a, f_s);
+
+a:keyword | f_s:keyword | f_l:boolean
+🐱Meow!🐶Woof! | Meow!🐶Woof! | true
+;
+
+containsNestedCase#[skip:-9.2.99,reason:new string function added in 9.3]
+row a = "hello" | eval a_ll = CASE(contains(a, "ll"), "success","fail");
+
+a:keyword | a_ll:keyword
+hello | success
+;
+
+containsNestSubstring#[skip:-9.2.99,reason:new string function added in 9.3]
+row a = "hello" | eval a_ll = contains(substring(a, 2), "ll");
+
+a:keyword | a_ll:boolean
+hello | true
+;
+
+containsWarnings#[skip:-9.2.99,reason:new string function added in 9.3]
+
+from hosts | where host=="epsilon" | eval l1 = contains(host_group, "ate"), l2 = contains(description, "ate") | keep l1, l2;
+ignoreOrder:true
+warning:Line 1:82: evaluation of [contains(description, \"ate\")] failed, treating result as null. Only first 20 failures recorded.
+warning:Line 1:82: java.lang.IllegalArgumentException: single-value function encountered multi-value
+
+l1:boolean | l2:boolean
+true          | null
+true          | null
+null       | false
+;
+
 // Note: no matches in MV returned
 in