Support parse more variant cases.

core/src/main/java/com/alibaba/druid/sql/ast/expr/SQLBinaryOperator.java

@@ -99,6 +99,7 @@ public enum SQLBinaryOperator {
     BooleanXor("XOR", 150),
     BooleanOr("OR", 160),
     Assignment(":=", 169),
+    Blank("", 170),
 
     PG_And("&&", 140),
     PG_ST_DISTANCE("<->", 20);

core/src/main/java/com/alibaba/druid/sql/parser/SQLExprParser.java

@@ -3532,6 +3532,9 @@ public class SQLExprParser extends SQLParser {
                 SQLBinaryOperator operator = andRestGetAndOperator();
 
                 expr = new SQLBinaryOpExpr(expr, operator, rightExp, dbType);
+            } else if (token == VARIANT) {
+                expr = new SQLBinaryOpExpr(expr, SQLBinaryOperator.Blank, new SQLVariantRefExpr(lexer.stringVal()), dbType);
+                lexer.nextToken();
             } else {
                 break;
             }
@@ -3977,6 +3980,11 @@ public class SQLExprParser extends SQLParser {
                     return expr;
                 }
                 break;
+            case VARIANT:
+                rightExp = new SQLVariantRefExpr(lexer.stringVal);
+                expr = new SQLBinaryOpExpr(expr, SQLBinaryOperator.Blank, rightExp, dbType);
+                lexer.nextToken();
+                return expr;
             default:
                 return expr;
         }

core/src/main/java/com/alibaba/druid/sql/parser/SQLSelectParser.java

@@ -756,6 +756,7 @@ public class SQLSelectParser extends SQLParser {
                     case BANGEQ:
                     case LIKE:
                     case NOT:
+                    case VARIANT:
                         where = this.exprParser.relationalRest(where);
                         break;
                     default:

core/src/main/java/com/alibaba/druid/sql/visitor/SQLASTOutputVisitor.java

@@ -1048,7 +1048,7 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter implements Paramet
                         && ((SQLIdentifierExpr) right).getName().equalsIgnoreCase("NOTFOUND")) {
                     printOpSpace = false;
                 }
-                if (printOpSpace) {
+                if (printOpSpace && operator != SQLBinaryOperator.Blank) {
                     print(' ');
                 }
             }

core/src/test/resources/bvt/parser/clickhouse/0.txt

@@ -1,3 +1,14 @@
+select c from b where c=1 ${if(len(a)=0,'and 1=1',"and a>0")} ${if(len(a)=0,'and 1=1',"and a>0")}
+--------------------
+SELECT c
+FROM b
+WHERE c = 1 ${if(len(a)=0,'and 1=1',"and a>0")} ${if(len(a)=0,'and 1=1',"and a>0")}
+------------------------------------------------------------------------------------------------------------------------
+select  ${if(len(a)=0,' 1=1 ',"c")}， ${if(len(a)=0,' 1=1 ',"c")} from b
+--------------------
+SELECT ${if(len(a)=0,' 1=1 ',"c")}, ${if(len(a)=0,' 1=1 ',"c")}
+FROM b
+------------------------------------------------------------------------------------------------------------------------
 --test
 select a from b
 --------------------