Add support for variable support to "SELECT SKIP <ROWCOUNT> FIRST <RO…

…WCOUNT>..." construct

The grammar for the construct in informix [1] mentions the possibility, that <ROWCOUNT> can be either
an integer or a host variable or local SPL variable storing the value of max. The case for plain integers and
jdbc variables is covered by the first commit While this commit adds support for constructs using SPL
variables. SPL variables must follow identifier rules [2][3].

[1] http://www-01.ibm.com/support/knowledgecenter/SSGU8G_12.1.0/com.ibm.sqls.doc/ids_sqs_0156.htm
[2] http://www-01.ibm.com/support/knowledgecenter/SSGU8G_12.1.0/com.ibm.sqls.doc/ids_sqs_1306.htm?lang=de
[3] http://www-01.ibm.com/support/knowledgecenter/SSGU8G_12.1.0/com.ibm.sqls.doc/ids_sqs_1660.htm%23ids_sqs_1660?lang=de

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

@@ -39,6 +39,7 @@ public enum Keyword {
     private Keyword keyword;
     private Long rowCount;
     private JdbcParameter jdbcParameter;
+    private String variable;
 
     public Long getRowCount() {
         return rowCount;
@@ -64,11 +65,25 @@ public void setKeyword(Keyword keyword) {
         this.keyword = keyword;
     }
 
+    public String getVariable() {
+        return variable;
+    }
+
+    public void setVariable(String variable) {
+        this.variable = variable;
+    }
+
     @Override
     public String toString() {
         String result = keyword.name() + " ";
 
-        result += jdbcParameter != null ? jdbcParameter.toString() : rowCount;
+        if(rowCount != null) {
+            result += rowCount;
+        } else if (jdbcParameter != null) {
+            result += jdbcParameter.toString();
+        } else if (variable != null){
+            result += variable;
+        }
 
         return result;
     }

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

@@ -33,6 +33,7 @@ public class Skip {
 
     private Long rowCount;
     private JdbcParameter jdbcParameter;
+    private String variable;
 
     public Long getRowCount() {
         return rowCount;
@@ -50,11 +51,25 @@ public void setJdbcParameter(JdbcParameter jdbcParameter) {
         this.jdbcParameter = jdbcParameter;
     }
 
+    public String getVariable() {
+        return variable;
+    }
+
+    public void setVariable(String variable) {
+        this.variable = variable;
+    }
+
     @Override
     public String toString() {
         String result = "SKIP ";
 
-        result += jdbcParameter != null ? jdbcParameter.toString() : rowCount;
+        if(rowCount != null) {
+            result += rowCount;
+        } else if (jdbcParameter != null) {
+            result += jdbcParameter.toString();
+        } else if (variable != null){
+            result += variable;
+        }
 
         return result;
     }

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

@@ -1315,6 +1315,7 @@ Skip Skip():
 	<K_SKIP>
 	(
 	 	token=<S_LONG>                      { skip.setRowCount(Long.parseLong(token.image)); }
+                | token=<S_IDENTIFIER>              { skip.setVariable(token.image); }
                 | "?" { skip.setJdbcParameter(new JdbcParameter()); } [ LOOKAHEAD(2) token = <S_LONG> { skip.getJdbcParameter().setIndex(Integer.valueOf(token.image)); } ]
 	)
 	{
@@ -1333,6 +1334,7 @@ First First():
         )
 	(
 	 	token=<S_LONG>                      { first.setRowCount(Long.parseLong(token.image)); }
+                | token=<S_IDENTIFIER>              { first.setVariable(token.image); }
                 |  "?" { first.setJdbcParameter(new JdbcParameter()); } [ LOOKAHEAD(2) token = <S_LONG> { first.getJdbcParameter().setIndex(Integer.valueOf(token.image)); } ]
 	)
 	{

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

@@ -437,13 +437,31 @@ public void testSkip() throws JSQLParserException {
         final Skip skip = selectBody.getSkip();
         assertEquals((long) 5, (long) skip.getRowCount());
         assertNull(skip.getJdbcParameter());
+        assertNull(skip.getVariable());
 
         final List<SelectItem> selectItems = selectBody.getSelectItems();
         assertEquals(2, selectItems.size());
         assertEquals(firstColumnName, selectItems.get(0).toString());
         assertEquals(secondColumnName, selectItems.get(1).toString());
 
         assertStatementCanBeDeparsedAs(select, statement);
+
+        final String statement2 = "SELECT SKIP skipVar c1, c2 FROM t";
+        final Select select2 = (Select) parserManager.parse(new StringReader(statement2));
+
+        final PlainSelect selectBody2 = (PlainSelect) select2.getSelectBody();
+
+        final Skip skip2 = selectBody2.getSkip();
+        assertNull(skip2.getRowCount());
+        assertNull(skip2.getJdbcParameter());
+        assertEquals("skipVar", skip2.getVariable());
+
+        final List<SelectItem> selectItems2 = selectBody2.getSelectItems();
+        assertEquals(2, selectItems2.size());
+        assertEquals("c1", selectItems2.get(0).toString());
+        assertEquals("c2", selectItems2.get(1).toString());
+
+        assertStatementCanBeDeparsedAs(select2, statement2);
     }
 
     public void testFirst() throws JSQLParserException {
@@ -465,6 +483,24 @@ public void testFirst() throws JSQLParserException {
         assertEquals(secondColumnName, selectItems.get(1).toString());
 
         assertStatementCanBeDeparsedAs(select, statement);
+
+
+        final String statement2 = "SELECT FIRST firstVar c1, c2 FROM t";
+        final Select select2 = (Select) parserManager.parse(new StringReader(statement2));
+
+        final PlainSelect selectBody2 = (PlainSelect) select2.getSelectBody();
+
+        final First first2 = selectBody2.getFirst();
+        assertNull(first2.getRowCount());
+        assertNull(first2.getJdbcParameter());
+        assertEquals("firstVar", first2.getVariable());
+
+        final List<SelectItem> selectItems2 = selectBody2.getSelectItems();
+        assertEquals(2, selectItems2.size());
+        assertEquals("c1", selectItems2.get(0).toString());
+        assertEquals("c2", selectItems2.get(1).toString());
+
+        assertStatementCanBeDeparsedAs(select2, statement2);
     }
 
     public void testFirstWithKeywordLimit() throws JSQLParserException {
@@ -490,7 +526,7 @@ public void testFirstWithKeywordLimit() throws JSQLParserException {
     }
 
     public void testSkipFirst() throws JSQLParserException {
-        final String statement = "SELECT SKIP ?1 FIRST ?2 c1, c2 FROM t1";
+        final String statement = "SELECT SKIP ?1 FIRST f1 c1, c2 FROM t1";
         final Select select = (Select) parserManager.parse(new StringReader(statement));
 
         final PlainSelect selectBody = (PlainSelect) select.getSelectBody();
@@ -499,11 +535,12 @@ public void testSkipFirst() throws JSQLParserException {
         assertNotNull(skip.getJdbcParameter());
         assertNotNull(skip.getJdbcParameter().getIndex());
         assertEquals((int) 1, (int) skip.getJdbcParameter().getIndex());
+        assertNull(skip.getVariable());
         final First first = selectBody.getFirst();
-        assertNotNull(first.getJdbcParameter());
-        assertNotNull(first.getJdbcParameter().getIndex());
-        assertEquals((int) 2, (int) first.getJdbcParameter().getIndex());
-
+        assertNull(first.getJdbcParameter());
+        assertNull(first.getRowCount());
+        assertEquals("f1", first.getVariable());
+        
         final List<SelectItem> selectItems = selectBody.getSelectItems();
         assertEquals(2, selectItems.size());
         assertEquals("c1", selectItems.get(0).toString());