[SQL] support StringLiteral try to cast BigInt (#4445)

fe/fe-core/src/main/java/org/apache/doris/analysis/BinaryPredicate.java

@@ -307,6 +307,28 @@ public class BinaryPredicate extends Predicate implements Writable {
             return Type.LARGEINT;
         }
 
+        // Implicit conversion affects query performance.
+        // For a common example datekey='20200825' which datekey is int type.
+        // If we up conversion to double type directly.
+        // PartitionPruner will not take effect. Then it will scan all partitions.
+        // When int column compares with string, Mysql will convert string to int.
+        // So it is also compatible with Mysql.
+
+        if (t1 == PrimitiveType.BIGINT && t2 == PrimitiveType.VARCHAR) {
+            Expr rightChild = getChild(1);
+            Long parsedLong = Type.tryParseToLong(rightChild);
+            if(parsedLong != null) {
+                return Type.BIGINT;
+            }
+        }
+        if (t1 == PrimitiveType.VARCHAR && t2 == PrimitiveType.BIGINT) {
+            Expr leftChild = getChild(0);
+            Long parsedLong = Type.tryParseToLong(leftChild);
+            if(parsedLong != null) {
+                return Type.BIGINT;
+            }
+        }
+
         return Type.DOUBLE;
     }
 

fe/fe-core/src/main/java/org/apache/doris/catalog/Type.java

@@ -386,6 +386,18 @@ public abstract class Type {
         return ScalarType.INVALID;
     }
 
+    /**
+     * Returns null if this expr is not instance of StringLiteral or StringLiteral
+     * inner value could not parse to long. otherwise return parsed Long result.
+     */
+    public static Long tryParseToLong(Expr expectStringExpr){
+        if (expectStringExpr instanceof StringLiteral) {
+            String value = ((StringLiteral)expectStringExpr).getValue();
+            return Longs.tryParse(value);
+        }
+        return null;
+    }
+
     /**
      * Returns true if this type exceeds the MAX_NESTING_DEPTH, false otherwise.
      */

fe/fe-core/src/test/java/org/apache/doris/analysis/SelectStmtTest.java

@@ -50,9 +50,25 @@ public class SelectStmtTest {
                 + "AGGREGATE KEY(k1, k2,k3,k4) distributed by hash(k1) buckets 3 properties('replication_num' = '1');";
         String createBaseAllStmtStr = "create table db1.baseall(k1 int, k2 varchar(32)) distributed by hash(k1) "
                 + "buckets 3 properties('replication_num' = '1');";
+        String createPratitionTableStr = "CREATE TABLE db1.partition_table (\n" +
+                "datekey int(11) NULL COMMENT \"datekey\",\n" +
+                "poi_id bigint(20) NULL COMMENT \"poi_id\"\n" +
+                ") ENGINE=OLAP\n" +
+                "AGGREGATE KEY(datekey, poi_id)\n" +
+                "COMMENT \"OLAP\"\n" +
+                "PARTITION BY RANGE(datekey)\n" +
+                "(PARTITION p20200727 VALUES [(\"20200726\"), (\"20200727\")),\n" +
+                "PARTITION p20200728 VALUES [(\"20200727\"), (\"20200728\")))\n" +
+                "DISTRIBUTED BY HASH(poi_id) BUCKETS 2\n" +
+                "PROPERTIES (\n" +
+                "\"storage_type\" = \"COLUMN\",\n" +
+                "\"replication_num\" = \"1\"\n" +
+                ");";
         dorisAssert = new DorisAssert();
         dorisAssert.withDatabase("db1").useDatabase("db1");
-        dorisAssert.withTable(createTblStmtStr).withTable(createBaseAllStmtStr);
+        dorisAssert.withTable(createTblStmtStr)
+                   .withTable(createBaseAllStmtStr)
+                   .withTable(createPratitionTableStr);
     }
 
     @Test
@@ -362,4 +378,22 @@ public class SelectStmtTest {
                 "from information_schema.collations";
         dorisAssert.query(sql).explainQuery();
     }
+
+    @Test
+    public void testVarcharToLongSupport() throws Exception {
+        String sql = "select count(*)\n" +
+                "from db1.partition_table\n" +
+                "where datekey='20200730'";
+        Assert.assertTrue(dorisAssert
+                .query(sql)
+                .explainQuery()
+                .contains("`datekey` = 20200730"));
+        sql = "select count(*)\n" +
+                "from db1.partition_table\n" +
+                "where '20200730'=datekey";
+        Assert.assertTrue(dorisAssert
+                .query(sql)
+                .explainQuery()
+                .contains("`datekey` = 20200730"));
+    }
 }