Discard table hints in MSSQLServer mode

Ignore table hints (e.g. "SELECT * FROM table WITH (NOLOCK)"), that form a
valid expression in SQL Server.

Reference:
https://docs.microsoft.com/en-us/sql/t-sql/queries/hints-transact-sql-table?view=sql-server-2017

h2/src/main/org/h2/command/Parser.java

@@ -1802,6 +1802,11 @@ public class Parser {
                 }
             }
         }
+
+        if (database.getMode().discardWithTableHints) {
+            discardWithTableHints();
+        }
+
         // inherit alias for CTE as views from table name
         if (table.isView() && table.isTableExpression() && alias == null) {
             alias = table.getName();
@@ -1855,6 +1860,34 @@ public class Parser {
         return null;
     }
 
+    private void discardWithTableHints() {
+        if (readIf("WITH")) {
+            read(OPEN_PAREN);
+            if (!readIf(CLOSE_PAREN)) {
+                do {
+                    discardTableHint();
+                } while (readIfMore(true));
+            }
+        }
+    }
+
+    private void discardTableHint() {
+        if (readIf("INDEX")) {
+            if (readIf(OPEN_PAREN)) {
+                do {
+                    readExpression();
+                } while (readIf(COMMA));
+                read(CLOSE_PAREN);
+            } else if (readIf(EQUAL)){
+                readExpression();
+            } else {
+                throw getSyntaxError();
+            }
+        } else {
+            readExpression();
+        }
+    }
+
     private Prepared parseTruncate() {
         read("TABLE");
         Table table = readTableOrView();

h2/src/main/org/h2/engine/Mode.java

@@ -187,6 +187,11 @@ public class Mode {
      */
     public boolean allowDB2TimestampFormat;
 
+    /**
+     * Discard SQLServer table hints (e.g. "SELECT * FROM table WITH (NOLOCK)")
+     */
+    public boolean discardWithTableHints;
+
     /**
      * Convert (VAR)CHAR to VAR(BINARY) and vice versa with UTF-8 encoding instead of HEX.
      */
@@ -256,6 +261,7 @@ public class Mode {
         mode.allowPlusForStringConcat = true;
         mode.swapConvertFunctionParameters = true;
         mode.supportPoundSymbolForColumnNames = true;
+        mode.discardWithTableHints = true;
         // MS SQL Server does not support client info properties. See
         // https://msdn.microsoft.com/en-Us/library/dd571296%28v=sql.110%29.aspx
         mode.supportedClientInfoPropertiesRegEx = null;

h2/src/test/org/h2/test/TestAll.java

@@ -30,6 +30,7 @@ import org.h2.test.db.TestCheckpoint;
 import org.h2.test.db.TestCluster;
 import org.h2.test.db.TestCompatibility;
 import org.h2.test.db.TestCompatibilityOracle;
+import org.h2.test.db.TestCompatibilitySQLServer;
 import org.h2.test.db.TestCsv;
 import org.h2.test.db.TestDateStorage;
 import org.h2.test.db.TestDeadlock;
@@ -745,6 +746,7 @@ kill -9 `jps -l | grep "org.h2.test." | cut -d " " -f 1`
         addTest(new TestCheckpoint());
         addTest(new TestCompatibility());
         addTest(new TestCompatibilityOracle());
+        addTest(new TestCompatibilitySQLServer());
         addTest(new TestCsv());
         addTest(new TestDeadlock());
         if (vmlens) {

h2/src/test/org/h2/test/db/TestCompatibilitySQLServer.java

+package org.h2.test.db;
+
+import org.h2.test.TestBase;
+import org.h2.test.TestDb;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+/**
+ * Test MSSQLServer compatibility mode.
+ */
+public class TestCompatibilitySQLServer extends TestDb {
+
+    /**
+     * Run just this test.
+     *
+     * @param s ignored
+     */
+    public static void main(String... s) throws Exception {
+        TestBase test = TestBase.createCaller().init();
+        test.test();
+    }
+
+    @Override
+    public void test() throws Exception {
+        testDiscardTableHints();
+    }
+
+    private void testDiscardTableHints() throws SQLException {
+        deleteDb("sqlserver");
+
+        Connection conn = getConnection("sqlserver;MODE=MSSQLServer");
+        Statement stat = conn.createStatement();
+
+        stat.execute("create table parent(id int primary key, name varchar(255))");
+        stat.execute("create table child(id int primary key, parent_id int, name varchar(255), foreign key (parent_id) references public.parent(id))");
+        
+        assertSupportedSyntax(stat, "select * from parent");
+        assertSupportedSyntax(stat, "select * from parent with(nolock)");
+        assertSupportedSyntax(stat, "select * from parent with(nolock, index = id)");
+        assertSupportedSyntax(stat, "select * from parent with(nolock, index(id, name))");
+
+        assertSupportedSyntax(stat, "select * from parent p join child ch on ch.parent_id = p.id");
+        assertSupportedSyntax(stat, "select * from parent p with(nolock) join child ch with(nolock) on ch.parent_id = p.id");
+        assertSupportedSyntax(stat, "select * from parent p with(nolock) join child ch with(nolock, index = id) on ch.parent_id = p.id");
+        assertSupportedSyntax(stat, "select * from parent p with(nolock) join child ch with(nolock, index(id, name)) on ch.parent_id = p.id");
+    }
+
+    private void assertSupportedSyntax(Statement stat, String sql) {
+        try {
+            stat.execute(sql);
+        } catch (SQLException ex) {
+            fail("Failed to execute SQL statement: " + sql);
+        }
+    }
+}