SQL: Scripting support for casting functions CAST and CONVERT (#36640)

x-pack/plugin/sql/qa/src/main/resources/agg.csv-spec

@@ -130,7 +130,7 @@ SELECT MAX(languages) max, MIN(languages) min, SUM(languages) sum, AVG(languages
        FROM test_emp GROUP BY languages ORDER BY languages ASC LIMIT 5;
 
       max:bt   |      min:bt   |      sum:bt   |      avg:d   |    percent:d  | percent_rank:d|   kurtosis:d  |   skewness:d    
----------------+---------------+---------------+---------------+---------------+---------------+---------------+---------------
+---------------+---------------+---------------+--------------+---------------+---------------+---------------+---------------
 null           |null           |null           |null          |null           |null           |null           |null           
 1              |1              |15             |1             |1.0            |100.0          |NaN            |NaN            
 2              |2              |38             |2             |2.0            |100.0          |NaN            |NaN            
@@ -138,6 +138,60 @@ null           |null           |null           |null           |null           |
 4              |4              |72             |4             |4.0            |0.0            |NaN            |NaN   
 ;
 
+aggByComplexCastedValue
+SELECT CONVERT(CONCAT(LTRIM(CONVERT("emp_no", SQL_VARCHAR)), LTRIM(CONVERT("languages", SQL_VARCHAR))), SQL_BIGINT) AS "TEMP"
+FROM "test_emp" GROUP BY "TEMP" ORDER BY "TEMP" LIMIT 20;
+
+    TEMP:l      
+---------------
+10020          
+10021          
+10022          
+10023          
+10024          
+10025          
+10026          
+10027          
+10028          
+10029          
+100012         
+100025         
+100034         
+100045         
+100051         
+100063         
+100074         
+100082         
+100091         
+100104         
+;
+
+aggAndOrderByCastedValue
+SELECT CHAR_LENGTH(SPACE(CAST(languages AS SMALLINT))), COUNT(*) FROM test_emp GROUP BY 1 ORDER BY 1 DESC;
+
+CHAR_LENGTH(SPACE(CAST(languages AS SMALLINT))):i|   COUNT(1):l
+-------------------------------------------------+---------------
+5                                                |21
+4                                                |18
+3                                                |17
+2                                                |19
+1                                                |15
+null                                             |10
+;
+
+aggAndOrderByCastedFunctionValue
+SELECT ROUND(SQRT(CAST(EXP(languages) AS SMALLINT)), 2), COUNT(*) FROM test_emp GROUP BY 1 ORDER BY 1 DESC;
+
+ROUND(SQRT(CAST(EXP(languages) AS SMALLINT)),2):d|  COUNT(1):l
+-------------------------------------------------+---------------
+12.17                                            |21
+7.42                                             |18
+4.47                                             |17
+2.65                                             |19
+1.73                                             |15
+null                                             |10
+;
+
 
 //
 // Grouping functions

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/function/scalar/Cast.java

@@ -7,14 +7,18 @@ package org.elasticsearch.xpack.sql.expression.function.scalar;
 
 import org.elasticsearch.xpack.sql.expression.Expression;
 import org.elasticsearch.xpack.sql.expression.gen.processor.Processor;
+import org.elasticsearch.xpack.sql.expression.gen.script.ScriptTemplate;
 import org.elasticsearch.xpack.sql.tree.Location;
 import org.elasticsearch.xpack.sql.tree.NodeInfo;
 import org.elasticsearch.xpack.sql.type.DataType;
 import org.elasticsearch.xpack.sql.type.DataTypeConversion;
 import org.elasticsearch.xpack.sql.type.DataTypes;
 
+import java.util.Locale;
 import java.util.Objects;
 
+import static org.elasticsearch.xpack.sql.expression.gen.script.ParamsBuilder.paramsBuilder;
+
 public class Cast extends UnaryScalarFunction {
 
     private final DataType dataType;
@@ -74,6 +78,18 @@ public class Cast extends UnaryScalarFunction {
         return new CastProcessor(DataTypeConversion.conversionFor(from(), to()));
     }
 
+    @Override
+    public ScriptTemplate asScript() {
+        ScriptTemplate fieldAsScript = asScript(field());
+        return new ScriptTemplate(
+                formatTemplate(String.format(Locale.ROOT, "{sql}.cast(%s,{})", fieldAsScript.template())),
+                paramsBuilder()
+                    .script(fieldAsScript.params())
+                    .variable(dataType.name())
+                    .build(),
+                dataType());
+    }
+
     @Override
     public int hashCode() {
         return Objects.hash(super.hashCode(), dataType);

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/expression/function/scalar/whitelist/InternalSqlScriptUtils.java

@@ -35,6 +35,7 @@ import org.elasticsearch.xpack.sql.expression.predicate.operator.comparison.Bina
 import org.elasticsearch.xpack.sql.expression.predicate.operator.comparison.InProcessor;
 import org.elasticsearch.xpack.sql.expression.predicate.regex.RegexProcessor.RegexOperation;
 import org.elasticsearch.xpack.sql.type.DataType;
+import org.elasticsearch.xpack.sql.type.DataTypeConversion;
 import org.elasticsearch.xpack.sql.util.DateUtils;
 import org.elasticsearch.xpack.sql.util.StringUtils;
 
@@ -458,4 +459,11 @@ public final class InternalSqlScriptUtils {
     public static String ucase(String s) {
         return (String) StringOperation.UCASE.apply(s);
     }
+    
+    //
+    // Casting
+    //
+    public static Object cast(Object value, String typeName) {
+        return DataTypeConversion.convert(value, DataType.fromTypeName(typeName));
+    }
 }

x-pack/plugin/sql/src/main/resources/org/elasticsearch/xpack/sql/plugin/sql_whitelist.txt

@@ -130,4 +130,9 @@ class org.elasticsearch.xpack.sql.expression.function.scalar.whitelist.InternalS
   String  space(Number)
   String  substring(String, Number, Number)
   String  ucase(String)
+  
+#
+# Casting
+#
+  def cast(Object, String)
 }

x-pack/plugin/sql/src/test/java/org/elasticsearch/xpack/sql/planner/QueryFolderTests.java

@@ -240,10 +240,10 @@ public class QueryFolderTests extends ESTestCase {
         assertEquals(EsQueryExec.class, p.getClass());
         EsQueryExec ee = (EsQueryExec) p;
         assertThat(ee.queryContainer().aggs().asAggBuilder().toString().replaceAll("\\s+", ""),
-            endsWith("{\"script\":{" +
+            endsWith("{\"script\":{\"source\":\"InternalSqlScriptUtils.cast(" +
-                "\"source\":\"InternalSqlScriptUtils.docValue(doc,params.v0)\",\"lang\":\"painless\"," +
+                    "InternalSqlScriptUtils.docValue(doc,params.v0),params.v1)\"," +
-                "\"params\":{\"v0\":\"keyword\"}},\"missing_bucket\":true," +
+                    "\"lang\":\"painless\",\"params\":{\"v0\":\"keyword\",\"v1\":\"IP\"}}," +
-                "\"value_type\":\"ip\",\"order\":\"asc\"}}}]}}}"));
+                    "\"missing_bucket\":true,\"value_type\":\"ip\",\"order\":\"asc\"}}}]}}}"));
         assertEquals(2, ee.output().size());
         assertThat(ee.output().get(0).toString(), startsWith("COUNT(1){a->"));
         assertThat(ee.output().get(1).toString(), startsWith("a{s->"));