Add support for Hive's LEFT SEMI JOIN

Author: nhanitvn

src/main/java/net/sf/jsqlparser/statement/select/Join.java

@@ -39,6 +39,7 @@ public class Join {
 	private boolean inner = false;
 	private boolean simple = false;
 	private boolean cross = false;
+	private boolean semi = false;
 	private FromItem rightItem;
 	private Expression onExpression;
 	private List<Column> usingColumns;
@@ -82,6 +83,15 @@ public void setOuter(boolean b) {
 		outer = b;
 	}
 
+	/**
+	 * Whether is a "SEMI" join
+	 *
+	 * @return true if is a "SEMI" join
+	 */
+	public boolean isSemi() { return semi; }
+
+	public void setSemi(boolean b) { semi = b; }
+
 	/**
 	 * Whether is a "LEFT" join
 	 *
@@ -199,6 +209,8 @@ public String toString() {
 				type += "OUTER ";
 			} else if (isInner()) {
 				type += "INNER ";
+			} else if (isSemi()) {
+				type += "SEMI ";
 			}
 
 			return type + "JOIN " + rightItem + ((onExpression != null) ? " ON " + onExpression + "" : "")

src/main/java/net/sf/jsqlparser/util/deparser/SelectDeParser.java

@@ -338,6 +338,8 @@ public void deparseJoin(Join join) {
                 buffer.append(" OUTER");
             } else if (join.isInner()) {
                 buffer.append(" INNER");
+            } else if (join.isSemi()) {
+                buffer.append(" SEMI");
             }
 
             buffer.append(" JOIN ");

src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt

@@ -232,6 +232,7 @@ TOKEN: /* SQL Keywords. prefixed with K_ to avoid name clashes */
 |	<K_DELAYED : "DELAYED">
 |	<K_HIGH_PRIORITY : "HIGH_PRIORITY">
 |	<K_IGNORE : "IGNORE">
+|   <K_SEMI : "SEMI">
 }
 
 TOKEN : /* Operators */
@@ -1224,9 +1225,9 @@ Join JoinerExpression():
 	List<Column> columns = null;
 }
 {
-    [   
-           ( <K_LEFT> { join.setLeft(true); }
-  		   | <K_RIGHT> { join.setRight(true); }
+    [
+  		<K_LEFT> { join.setLeft(true); } [ <K_SEMI> { join.setSemi(true); } | <K_OUTER> { join.setOuter(true); } ]
+  		|  ( <K_RIGHT> { join.setRight(true); }
   		   | <K_FULL> { join.setFull(true); } 
            ) [ <K_OUTER> { join.setOuter(true); } ]
         | <K_INNER> { join.setInner(true); }