Support queries end with semi colon (#609)

* Change grammar and add UT

* Add doc

* Move IT

docs/user/dql/basics.rst

@@ -28,6 +28,8 @@ The syntax of ``SELECT`` statement is as follows::
   [ORDER BY expression [IS [NOT] NULL] [ASC | DESC] [, ...]]
   [LIMIT [offset, ] size]
 
+Although multiple query statements to execute in batch is not supported, ending with semicolon ``;`` is still allowed. For example, you can run ``SELECT * FROM accounts;`` without issue. This is useful to support queries generated by other tool, such as Microsoft Excel or BI tool.
+
 Fundamentals
 ------------
 

integ-test/build.gradle

@@ -137,6 +137,7 @@ task docTest(type: RestIntegTestTask) {
         include 'com/amazon/opendistroforelasticsearch/sql/doctest/**/*IT.class'
         exclude 'com/amazon/opendistroforelasticsearch/sql/correctness/**/*IT.class'
         exclude 'com/amazon/opendistroforelasticsearch/sql/ppl/**/*IT.class'
+        exclude 'com/amazon/opendistroforelasticsearch/sql/sql/**/*IT.class'
         exclude 'com/amazon/opendistroforelasticsearch/sql/legacy/**/*IT.class'
     }
 }

integ-test/src/test/java/com/amazon/opendistroforelasticsearch/sql/legacy/QueryIT.java

@@ -90,6 +90,11 @@ protected void init() throws Exception {
     loadIndex(Index.BANK_WITH_NULL_VALUES);
   }
 
+  @Test
+  public void queryEndWithSemiColonTest() {
+    executeQuery(StringUtils.format("SELECT * FROM %s;", TEST_INDEX_BANK), "jdbc");
+  }
+
   @Test
   public void searchTypeTest() throws IOException {
     JSONObject response = executeQuery(String.format(Locale.ROOT, "SELECT * FROM %s LIMIT 1000",

integ-test/src/test/resources/doctest/templates/dql/basics.rst

@@ -28,6 +28,8 @@ The syntax of ``SELECT`` statement is as follows::
   [ORDER BY expression [IS [NOT] NULL] [ASC | DESC] [, ...]]
   [LIMIT [offset, ] size]
 
+Although multiple query statements to execute in batch is not supported, ending with semicolon ``;`` is still allowed. For example, you can run ``SELECT * FROM accounts;`` without issue. This is useful to support queries generated by other tool, such as Microsoft Excel or BI tool.
+
 Fundamentals
 ------------
 

legacy/src/main/antlr/OpenDistroSqlParser.g4

@@ -32,7 +32,7 @@ options { tokenVocab=OpenDistroSqlLexer; }
 
 //    Root rule
 root
-    : sqlStatement? EOF
+    : sqlStatement? SEMI? EOF
     ;
 
 //    Only SELECT, DELETE, SHOW and DSCRIBE are supported for now

legacy/src/main/java/com/amazon/opendistroforelasticsearch/sql/legacy/query/ESActionFactory.java

@@ -87,8 +87,11 @@ public static QueryAction create(Client client, String sql)
     public static QueryAction create(Client client, QueryActionRequest request)
             throws SqlParseException, SQLFeatureNotSupportedException {
         String sql = request.getSql();
-        // Linebreak matcher
+        // Remove line breaker anywhere and semicolon at the end
         sql = sql.replaceAll("\\R", " ").trim();
+        if (sql.endsWith(";")) {
+            sql = sql.substring(0, sql.length() - 1);
+        }
 
         switch (getFirstWord(sql)) {
             case "SELECT":

legacy/src/test/java/com/amazon/opendistroforelasticsearch/sql/legacy/antlr/SyntaxAnalysisTest.java

@@ -79,7 +79,7 @@ public void missingWhereKeywordShouldThrowException() {
         expectValidationFailWithErrorMessage(
             "SELECT * FROM accounts age = 1",
             "offending symbol [=]", // parser thought 'age' is alias of 'accounts' and failed at '='
-            "Expecting", "'WHERE'"  // "Expecting tokens in {<EOF>, 'INNER', 'JOIN', ... 'WHERE', ','}"
+            "Expecting", ";"        // "Expecting tokens in {<EOF>, ';'}"
         );
     }
 
@@ -130,6 +130,11 @@ public void arithmeticExpressionInWhereClauseShouldPass() {
         validate("SELECT * FROM accounts WHERE age + 1 = 10");
     }
 
+    @Test
+    public void queryEndWithSemiColonShouldPass() {
+        validate("SELECT * FROM accounts;");
+    }
+
     private void expectValidationFailWithErrorMessage(String query, String... messages) {
         exception.expect(SyntaxAnalysisException.class);
         exception.expectMessage(allOf(Arrays.stream(messages).

sql/src/main/antlr/OpenDistroSQLParser.g4

@@ -34,7 +34,7 @@ options { tokenVocab=OpenDistroSQLLexer; }
 
 //    Root rule
 root
-    : sqlStatement? EOF
+    : sqlStatement? SEMI? EOF
     ;
 
 //    Only SELECT

sql/src/test/java/com/amazon/opendistroforelasticsearch/sql/sql/antlr/SQLSyntaxParserTest.java

@@ -26,6 +26,11 @@ class SQLSyntaxParserTest {
 
   private final SQLSyntaxParser parser = new SQLSyntaxParser();
 
+  @Test
+  public void canParseQueryEndWithSemiColon() {
+    assertNotNull(parser.parse("SELECT 123;"));
+  }
+
   @Test
   public void canParseSelectLiterals() {
     assertNotNull(parser.parse("SELECT 123, 'hello'"));