Add support for lag and lead with offset and default value parameters

Author: Jonathan Burnhams

src/main/java/net/sf/jsqlparser/expression/AnalyticExpression.java

@@ -21,10 +21,11 @@
  */
 package net.sf.jsqlparser.expression;
 
-import java.util.List;
 import net.sf.jsqlparser.schema.Column;
 import net.sf.jsqlparser.statement.select.OrderByElement;
 
+import java.util.List;
+
 /**
  * Analytic function. The name of the function is variable but the parameters
  * following the special analytic function path. e.g. row_number() over (order
@@ -39,6 +40,8 @@ public class AnalyticExpression implements Expression {
 	private List<OrderByElement> orderByElements;
 	private String name;
 	private Expression expression;
+    private Expression offset;
+    private Expression defaultValue;
 	private boolean allColumns = false;
 
 	@Override
@@ -78,13 +81,35 @@ public void setExpression(Expression expression) {
 		this.expression = expression;
 	}
 
-	@Override
+    public Expression getOffset() {
+        return offset;
+    }
+
+    public void setOffset(Expression offset) {
+        this.offset = offset;
+    }
+
+    public Expression getDefaultValue() {
+        return defaultValue;
+    }
+
+    public void setDefaultValue(Expression defaultValue) {
+        this.defaultValue = defaultValue;
+    }
+
+    @Override
 	public String toString() {
 		StringBuilder b = new StringBuilder();
 
 		b.append(name).append("(");
 		if (expression != null) {
 			b.append(expression.toString());
+            if (offset != null) {
+                b.append(", ").append(offset.toString());
+                if (defaultValue != null) {
+                    b.append(", ").append(defaultValue.toString());
+                }
+            }
 		} else if (isAllColumns()) {
 			b.append("*");
 		}

src/main/javacc/net/sf/jsqlparser/parser/JSqlParserCC.jj

@@ -1765,13 +1765,18 @@ AnalyticExpression AnalyticExpression() :
 	Token token = null;
 	Column column = null;
 	Expression expr = null;
+	Expression offset = null;
+	Expression defaultValue = null;
 }
 {
-	token=<S_IDENTIFIER> { retval.setName(token.image); } "(" [ expr=SimpleExpression() | "*" { retval.setAllColumns(true); } ] ")" <K_OVER> "(" 
+	token=<S_IDENTIFIER> { retval.setName(token.image); }
+	    "(" [ expr=SimpleExpression() ["," offset=SimpleExpression() ["," defaultValue=SimpleExpression() ]] | "*" { retval.setAllColumns(true); } ] ")" <K_OVER> "("
         [<K_PARTITION> <K_BY> column=Column() {plist.add(column);}  ("," column=Column() {plist.add(column);} )* ] 
         [olist=OrderByElements() ]
 	{
 		retval.setExpression(expr);
+		retval.setOffset(offset);
+		retval.setDefaultValue(defaultValue);
 		retval.setPartitionByColumns(plist);
 		retval.setOrderByElements(olist);
 	} 

src/test/java/net/sf/jsqlparser/test/select/SelectTest.java

@@ -775,6 +775,16 @@ public void testProblemSqlAnalytic9CommaListPartition() throws JSQLParserExcepti
 		assertSqlCanBeParsedAndDeparsed(stmt);
 	}
 
+    public void testProblemSqlAnalytic10Lag() throws JSQLParserException {
+        String stmt = "SELECT a, lag(a, 1) OVER (PARTITION BY c ORDER BY a, b) AS n FROM table1";
+        assertSqlCanBeParsedAndDeparsed(stmt);
+    }
+
+    public void testProblemSqlAnalytic11Lag() throws JSQLParserException {
+        String stmt = "SELECT a, lag(a, 1, 0) OVER (PARTITION BY c ORDER BY a, b) AS n FROM table1";
+        assertSqlCanBeParsedAndDeparsed(stmt);
+    }
+
 	public void testOracleJoin() throws JSQLParserException {
 		String stmt = "SELECT * FROM tabelle1, tabelle2 WHERE tabelle1.a = tabelle2.b(+)";
 		assertSqlCanBeParsedAndDeparsed(stmt);