Implement isBlank

docs/ppl-lang/PPL-Example-Commands.md

@@ -37,6 +37,7 @@ _- **Limitation: new field added by eval command with a function cannot be dropp
 - `source = table | where ispresent(b)`
 - `source = table | where isnull(coalesce(a, b)) | fields a,b,c | head 3`
 - `source = table | where isempty(a)`
+- `source = table | where isblank(a)`
 - `source = table | where case(length(a) > 6, 'True' else 'False') = 'True'`
 
 ```sql
@@ -82,6 +83,7 @@ Assumptions: `a`, `b`, `c` are existing fields in `table`
 - `source = table | eval f = ispresent(a)`
 - `source = table | eval r = coalesce(a, b, c) | fields r`
 - `source = table | eval e = isempty(a) | fields e`
+- `source = table | eval e = isblank(a) | fields e`
 - `source = table | eval f = case(a = 0, 'zero', a = 1, 'one', a = 2, 'two', a = 3, 'three', a = 4, 'four', a = 5, 'five', a = 6, 'six', a = 7, 'se7en', a = 8, 'eight', a = 9, 'nine')`
 - `source = table | eval f = case(a = 0, 'zero', a = 1, 'one' else 'unknown')`
 - `source = table | eval f = case(a = 0, 'zero', a = 1, 'one' else concat(a, ' is an incorrect binary digit'))`

docs/ppl-lang/ppl-eval-command.md

@@ -76,6 +76,7 @@ Assumptions: `a`, `b`, `c` are existing fields in `table`
 - `source = table | eval f = ispresent(a)`
 - `source = table | eval r = coalesce(a, b, c) | fields r`
 - `source = table | eval e = isempty(a) | fields e`
+- `source = table | eval e = isblank(a) | fields e`
 - `source = table | eval f = case(a = 0, 'zero', a = 1, 'one', a = 2, 'two', a = 3, 'three', a = 4, 'four', a = 5, 'five', a = 6, 'six', a = 7, 'se7en', a = 8, 'eight', a = 9, 'nine')`
 - `source = table | eval f = case(a = 0, 'zero', a = 1, 'one' else 'unknown')`
 - `source = table | eval f = case(a = 0, 'zero', a = 1, 'one' else concat(a, ' is an incorrect binary digit'))`

docs/ppl-lang/ppl-where-command.md

@@ -39,6 +39,7 @@ PPL query:
 - `source = table | where ispresent(b)`
 - `source = table | where isnull(coalesce(a, b)) | fields a,b,c | head 3`
 - `source = table | where isempty(a)`
+- `source = table | where isblank(a)`
 - `source = table | where case(length(a) > 6, 'True' else 'False') = 'True'`
 
 - `source = table | eval status_category =

integ-test/src/integration/scala/org/opensearch/flint/spark/ppl/FlintSparkPPLBuiltinFunctionITSuite.scala

@@ -382,6 +382,96 @@ class FlintSparkPPLBuiltinFunctionITSuite
     comparePlans(logicalPlan, expectedPlan, checkAnalysis = false)
   }
 
+  test("test string functions - isblank eval") {
+    val frame = sql(s"""
+                       | source = $testNullTable | head 1 | eval a = isblank('full'), b = isblank(''), c = isblank(' ') | fields a, b, c
+                       | """.stripMargin)
+
+    val results: Array[Row] = frame.collect()
+    val expectedResults: Array[Row] = Array(Row(false, true, true))
+    assert(results.sameElements(expectedResults))
+
+    val logicalPlan: LogicalPlan = frame.queryExecution.logical
+    val table = UnresolvedRelation(Seq("spark_catalog", "default", "flint_ppl_test_null"))
+    val localLimit = LocalLimit(Literal(1), table)
+    val globalLimit = GlobalLimit(Literal(1), localLimit)
+
+    //    val projectList = Seq(UnresolvedStar(None))
+
+    val caseOne = CaseWhen(
+      Seq(
+        (
+          EqualTo(
+            UnresolvedFunction(
+              "length",
+              Seq(UnresolvedFunction("trim", Seq(Literal("full")), isDistinct = false)),
+              isDistinct = false),
+            Literal(0)),
+          Literal(true))),
+      Literal(false))
+    val aliasOne = Alias(caseOne, "a")()
+
+    val caseTwo = CaseWhen(
+      Seq(
+        (
+          EqualTo(
+            UnresolvedFunction(
+              "length",
+              Seq(UnresolvedFunction("trim", Seq(Literal("")), isDistinct = false)),
+              isDistinct = false),
+            Literal(0)),
+          Literal(true))),
+      Literal(false))
+    val aliasTwo = Alias(caseTwo, "b")()
+
+    val caseThree = CaseWhen(
+      Seq(
+        (
+          EqualTo(
+            UnresolvedFunction(
+              "length",
+              Seq(UnresolvedFunction("trim", Seq(Literal(" ")), isDistinct = false)),
+              isDistinct = false),
+            Literal(0)),
+          Literal(true))),
+      Literal(false))
+    val aliasThree = Alias(caseThree, "c")()
+
+    val projectList = Seq(UnresolvedStar(None), aliasOne, aliasTwo, aliasThree)
+    val innerProject = Project(projectList, globalLimit)
+
+    val expectedPlan = Project(
+      Seq(UnresolvedAttribute("a"), UnresolvedAttribute("b"), UnresolvedAttribute("c")),
+      innerProject)
+    comparePlans(logicalPlan, expectedPlan, checkAnalysis = false)
+  }
+
+  test("test string functions - isblank where") {
+    val frame = sql(s"""
+                       | source = $testNullTable | where isblank('I am not blank');
+                       | """.stripMargin)
+    val results: Array[Row] = frame.collect()
+    assert(results.length == 0)
+
+    val logicalPlan: LogicalPlan = frame.queryExecution.logical
+
+    val table = UnresolvedRelation(Seq("spark_catalog", "default", "flint_ppl_test_null"))
+    val caseIsEmpty = CaseWhen(
+      Seq(
+        (
+          EqualTo(
+            UnresolvedFunction(
+              "length",
+              Seq(UnresolvedFunction("trim", Seq(Literal("I am not blank")), isDistinct = false)),
+              isDistinct = false),
+            Literal(0)),
+          Literal(true))),
+      Literal(false))
+    val filterPlan = Filter(caseIsEmpty, table)
+    val expectedPlan = Project(Seq(UnresolvedStar(None)), filterPlan)
+    comparePlans(logicalPlan, expectedPlan, checkAnalysis = false)
+  }
+
   test("test math functions - abs with field") {
     val frame = sql(s"""
        | source = $testTable |where abs(age) = 30 | fields name, age

ppl-spark-integration/src/main/antlr4/OpenSearchPPLLexer.g4

@@ -350,6 +350,7 @@ REPLACE:                            'REPLACE';
 REVERSE:                            'REVERSE';
 CAST:                               'CAST';
 ISEMPTY:                            'ISEMPTY';
+ISBLANK:                            'ISBLANK';
 
 // BOOL FUNCTIONS
 LIKE:                               'LIKE';

ppl-spark-integration/src/main/antlr4/OpenSearchPPLParser.g4

@@ -376,7 +376,7 @@ booleanExpression
    ;
 
  isEmptyExpression
-   : ISEMPTY LT_PRTHS functionArg RT_PRTHS
+   : (ISEMPTY | ISBLANK) LT_PRTHS functionArg RT_PRTHS
    ;
 
  caseFunction
@@ -745,6 +745,7 @@ textFunctionName
    | REPLACE
    | REVERSE
    | ISEMPTY
+   | ISBLANK
    ;
 
 positionFunctionName