Add support for ClickHouse PREWHERE clause

src/main/java/net/sf/jsqlparser/parser/ParserKeywordsUtils.java

@@ -121,6 +121,7 @@ public class ParserKeywordsUtils {
             {"OVERWRITE ", RESTRICTED_JSQLPARSER},
             {"PIVOT", RESTRICTED_JSQLPARSER},
             {"PREFERRING", RESTRICTED_JSQLPARSER},
+            {"PREWHERE", RESTRICTED_JSQLPARSER},
             {"PRIOR", RESTRICTED_ALIAS},
             {"PROCEDURE", RESTRICTED_ALIAS},
             {"PUBLIC", RESTRICTED_ALIAS},

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

@@ -37,6 +37,7 @@ public class PlainSelect extends Select {
     private FromItem fromItem;
     private List<LateralView> lateralViews;
     private List<Join> joins;
+    private Expression preWhere;
     private Expression where;
     private GroupByElement groupBy;
     private Expression having;
@@ -160,6 +161,14 @@ public void setWhere(Expression where) {
         this.where = where;
     }
 
+    public Expression getPreWhere() {
+        return preWhere;
+    }
+
+    public void setPreWhere(Expression preWhere) {
+        this.preWhere = preWhere;
+    }
+
     public PlainSelect withFromItem(FromItem item) {
         this.setFromItem(item);
         return this;
@@ -569,6 +578,9 @@ public StringBuilder appendSelectBodyTo(StringBuilder builder) {
             if (ksqlWindow != null) {
                 builder.append(" WINDOW ").append(ksqlWindow);
             }
+            if (preWhere != null) {
+                builder.append(" PREWHERE ").append(preWhere);
+            }
             if (where != null) {
                 builder.append(" WHERE ").append(where);
             }
@@ -597,6 +609,9 @@ public StringBuilder appendSelectBodyTo(StringBuilder builder) {
             }
         } else {
             // without from
+            if (preWhere != null) {
+                builder.append(" PREWHERE ").append(preWhere);
+            }
             if (where != null) {
                 builder.append(" WHERE ").append(where);
             }
@@ -669,6 +684,11 @@ public PlainSelect withWhere(Expression where) {
         return this;
     }
 
+    public PlainSelect withPreWhere(Expression preWhere) {
+        this.setPreWhere(preWhere);
+        return this;
+    }
+
     public PlainSelect withOptimizeFor(OptimizeFor optimizeFor) {
         this.setOptimizeFor(optimizeFor);
         return this;
@@ -767,6 +787,10 @@ public <E extends Expression> E getWhere(Class<E> type) {
         return type.cast(getWhere());
     }
 
+    public <E extends Expression> E getPreWhere(Class<E> type) {
+        return type.cast(getPreWhere());
+    }
+
     public <E extends Expression> E getHaving(Class<E> type) {
         return type.cast(getHaving());
     }

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

@@ -151,6 +151,7 @@ public <S> T visit(PlainSelect plainSelect, S context) {
         // //@todo: implement
         // }
 
+        expressionVisitor.visitExpression(plainSelect.getPreWhere(), context);
         expressionVisitor.visitExpression(plainSelect.getWhere(), context);
 
         // if (plainSelect.getOracleHierarchical() != null) {

src/main/java/net/sf/jsqlparser/util/TablesNamesFinder.java

@@ -317,6 +317,9 @@ public <S> Void visit(PlainSelect plainSelect, S context) {
         }
 
         visitJoins(plainSelect.getJoins(), context);
+        if (plainSelect.getPreWhere() != null) {
+            plainSelect.getPreWhere().accept(this, context);
+        }
         if (plainSelect.getWhere() != null) {
             plainSelect.getWhere().accept(this, context);
         }

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

@@ -287,6 +287,7 @@ public <S> StringBuilder visit(PlainSelect plainSelect, S context) {
             builder.append(plainSelect.getKsqlWindow().toString());
         }
 
+        deparsePreWhereClause(plainSelect);
         deparseWhereClause(plainSelect);
 
         if (plainSelect.getOracleHierarchical() != null) {
@@ -394,6 +395,13 @@ protected void deparseWhereClause(PlainSelect plainSelect) {
         }
     }
 
+    protected void deparsePreWhereClause(PlainSelect plainSelect) {
+        if (plainSelect.getPreWhere() != null) {
+            builder.append(" PREWHERE ");
+            plainSelect.getPreWhere().accept(expressionVisitor, null);
+        }
+    }
+
     protected void deparseDistinctClause(Distinct distinct) {
         if (distinct != null) {
             if (distinct.isUseUnique()) {

src/main/java/net/sf/jsqlparser/util/validation/validator/SelectValidator.java

@@ -119,6 +119,7 @@ public <S> Void visit(PlainSelect plainSelect, S context) {
         // validateOptionalList(plainSelect.getSelectItems(), () -> this, SelectItem::accept,
         // context);
 
+        validateOptionalExpression(plainSelect.getPreWhere());
         validateOptionalExpression(plainSelect.getWhere());
         validateOptionalExpression(plainSelect.getOracleHierarchical());
 

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

@@ -539,6 +539,7 @@ TOKEN: /* SQL Keywords. prefixed with K_ to avoid name clashes */
 |   <K_PLUS:"PLUS">
 |   <K_PREFERRING: "PREFERRING">
 |   <K_PRECEDING: "PRECEDING">
+|   <K_PREWHERE: "PREWHERE">
 |   <K_PRIMARY:"PRIMARY">
 |   <K_PRIOR:"PRIOR">
 |   <K_PROCEDURE:"PROCEDURE">
@@ -4118,6 +4119,7 @@ PlainSelect PlainSelect() #PlainSelect:
     List<LateralView> lateralViews = null;
     List<Join> joins = null;
     List<SelectItem<?>> distinctOn = null;
+    Expression preWhere = null;
     Expression where = null;
     ForClause forClause = null;
     List<OrderByElement> orderByElements;
@@ -4213,6 +4215,7 @@ PlainSelect PlainSelect() #PlainSelect:
     [ LOOKAHEAD(2) <K_FINAL> { plainSelect.setUsingFinal(true); } ]
 
     [ LOOKAHEAD(2) ksqlWindow=KSQLWindowClause() { plainSelect.setKsqlWindow(ksqlWindow); } ]
+    [ LOOKAHEAD(2) preWhere=PreWhereClause() { plainSelect.setPreWhere(preWhere); }]
     [ LOOKAHEAD(2) where=WhereClause() { plainSelect.setWhere(where); }]
     [ LOOKAHEAD(2) oracleHierarchicalQueryClause=OracleHierarchicalQueryClause() { plainSelect.setOracleHierarchical(oracleHierarchicalQueryClause); } ]
     [ LOOKAHEAD(2) preferringClause=PreferringClause() { plainSelect.setPreferringClause(preferringClause); }
@@ -5088,6 +5091,15 @@ Expression WhereClause():
     { return retval; }
 }
 
+Expression PreWhereClause():
+{
+    Expression retval = null;
+}
+{
+    <K_PREWHERE> retval=Expression()
+    { return retval; }
+}
+
 OracleHierarchicalExpression OracleHierarchicalQueryClause():
 {
     OracleHierarchicalExpression result = new OracleHierarchicalExpression();

src/test/java/net/sf/jsqlparser/statement/select/ClickHouseTest.java

@@ -59,4 +59,21 @@ public void execute() throws Throwable {
                     }
                 }, "Fail when restricted keyword GLOBAL is used as an Alias.");
     }
+
+    @Test
+    public void testPreWhereClause() throws JSQLParserException {
+        String sqlStr = "SELECT * FROM table1 PREWHERE column_name = 'value'";
+        PlainSelect select = (PlainSelect) assertSqlCanBeParsedAndDeparsed(sqlStr, true);
+        Assertions.assertNotNull(select.getPreWhere());
+        Assertions.assertNull(select.getWhere());
+    }
+
+    @Test
+    public void testPreWhereWithWhereClause() throws JSQLParserException {
+        String sqlStr =
+                "SELECT * FROM table1 PREWHERE column_name = 'value' WHERE id > 10";
+        PlainSelect select = (PlainSelect) assertSqlCanBeParsedAndDeparsed(sqlStr, true);
+        Assertions.assertNotNull(select.getPreWhere());
+        Assertions.assertNotNull(select.getWhere());
+    }
 }

src/test/java/net/sf/jsqlparser/util/TablesNamesFinderTest.java

@@ -55,6 +55,14 @@ public void testGetTablesWithXor() throws Exception {
         assertThat(TablesNamesFinder.findTables(sqlStr)).containsExactlyInAnyOrder("MY_TABLE1");
     }
 
+    @Test
+    public void testGetTablesWithPreWhere() throws Exception {
+        String sqlStr =
+                "SELECT * FROM MY_TABLE1 PREWHERE ID IN (SELECT ID FROM MY_TABLE2)";
+        assertThat(TablesNamesFinder.findTables(sqlStr)).containsExactlyInAnyOrder("MY_TABLE1",
+                "MY_TABLE2");
+    }
+
     @Test
     public void testGetTablesWithStmt() throws Exception {
         String sqlStr =
@@ -734,4 +742,3 @@ void testNestedTablesInJsonObject() throws JSQLParserException {
                 "table2", "table3");
     }
 }
-