improved postgresql sql parser support. support Polygon Operators. issue #1391

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

@@ -65,6 +65,7 @@ public enum SQLBinaryOperator {
     POSIX_Regular_Not_Match_POSIX_Regular_Match_Insensitive("!~*", 110),
     Array_Contains("@>", 110),
     Array_ContainedBy("<@", 110),
+    SAME_AS("~=", 110),
     
     RLike("RLIKE", 110),
     NotRLike("NOT RLIKE", 110),

src/main/java/com/alibaba/druid/sql/parser/Lexer.java

@@ -650,6 +650,9 @@ public class Lexer {
                 if (ch == '*') {
                     scanChar();
                     token = Token.TILDE_STAR;
+                } else if (ch == '=') {
+                    scanChar();
+                    token = Token.TILDE_EQ; // postsql
                 } else {
                     token = Token.TILDE;
                 }

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

@@ -51,6 +51,7 @@ import com.alibaba.druid.sql.ast.statement.SQLSelectItem;
 import com.alibaba.druid.sql.ast.statement.SQLSelectOrderByItem;
 import com.alibaba.druid.sql.ast.statement.SQLUnique;
 import com.alibaba.druid.sql.ast.statement.SQLUpdateSetItem;
+import com.alibaba.druid.sql.dialect.postgresql.ast.expr.PGPolygonExpr;
 import com.alibaba.druid.util.JdbcConstants;
 
 public class SQLExprParser extends SQLParser {
@@ -1534,6 +1535,14 @@ public class SQLExprParser extends SQLParser {
                 rightExp = relationalRest(rightExp);
 
                 expr = new SQLBinaryOpExpr(expr, SQLBinaryOperator.POSIX_Regular_Not_Match_POSIX_Regular_Match_Insensitive, rightExp, getDbType());
+            } else if (lexer.token() == Token.TILDE_EQ) {
+                lexer.nextToken();
+
+                rightExp = equality();
+
+                rightExp = relationalRest(rightExp);
+
+                expr = new SQLBinaryOpExpr(expr, SQLBinaryOperator.SAME_AS, rightExp, getDbType());
             }
         }
 

src/main/java/com/alibaba/druid/sql/parser/Token.java

@@ -303,6 +303,7 @@ public enum Token {
     BANG_TILDE_STAR("!~*"),
     TILDE("~"),
     TILDE_STAR("~*"),
+    TILDE_EQ("~="),
     QUES("?"), 
     COLON(":"), 
     COLONCOLON(":"),