From 5492f5105a757817c4d18119751006f9c1ccc32d Mon Sep 17 00:00:00 2001
From: Tomer S <shimshi.tomer@gmail.com>
Date: Fri, 26 Jul 2019 20:15:25 +0300
Subject: [PATCH] The duration part in INTERVAL expressions can contain a
 column and not only a constant - now supporting that use case

---
 .../jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt  | 11 +++++++++--
 .../sf/jsqlparser/statement/select/SelectTest.java    |  6 ++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt b/src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt
index adb6cd7c6..aff6dac8e 100644
--- a/src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt
+++ b/src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt
@@ -2955,13 +2955,20 @@ JsonExpression JsonExpression() : {
 
 IntervalExpression IntervalExpression() : {
     IntervalExpression interval;
+    Column col;
     Token token;
     boolean signed = false;
 }
 {
     { interval = new IntervalExpression(); }
-    <K_INTERVAL> ["-" {signed=true;}] (token=<S_LONG> | token=<S_DOUBLE> | token=<S_CHAR_LITERAL> ) 
-    { interval.setParameter((signed?"-":"") + token.image); }
+    <K_INTERVAL> ["-" {signed=true;}]
+    (
+        ((token=<S_LONG> | token=<S_DOUBLE> | token=<S_CHAR_LITERAL> )
+        { interval.setParameter((signed?"-":"") + token.image); })
+        |
+        (col=Column()
+        { interval.setExpression(col); })
+    )
     [ LOOKAHEAD(2) (token = <S_IDENTIFIER> | token = <K_DATE_LITERAL>) { interval.setIntervalType(token.image); } ]
     {
         return interval;
diff --git a/src/test/java/net/sf/jsqlparser/statement/select/SelectTest.java b/src/test/java/net/sf/jsqlparser/statement/select/SelectTest.java
index 2dd405a8c..6327368f8 100644
--- a/src/test/java/net/sf/jsqlparser/statement/select/SelectTest.java
+++ b/src/test/java/net/sf/jsqlparser/statement/select/SelectTest.java
@@ -2177,6 +2177,12 @@ public void testValues6BothVariants() throws JSQLParserException {
         assertSqlCanBeParsedAndDeparsed(stmt);
     }
 
+    @Test
+    public void testIntervalWithColumn() throws JSQLParserException {
+        String stmt = "SELECT DATE_ADD(start_date, INTERVAL duration MINUTE) AS end_datetime FROM appointment";
+        assertSqlCanBeParsedAndDeparsed(stmt);
+    }
+
     @Test
     public void testInterval1() throws JSQLParserException {
         String stmt = "SELECT 5 + INTERVAL '3 days'";