sql parser improved pg support, fix #4128

src/main/java/com/alibaba/druid/sql/ast/statement/SQLAlterTableStatement.java

@@ -53,6 +53,8 @@ public class SQLAlterTableStatement extends SQLStatementImpl implements SQLDDLSt
     protected int                   buckets;
     protected int                   shards;
 
+    private boolean                 ifExists                 = false;
+
     public SQLAlterTableStatement(){
 
     }
@@ -85,6 +87,14 @@ public class SQLAlterTableStatement extends SQLStatementImpl implements SQLDDLSt
         this.offline = offline;
     }
 
+    public boolean isIfExists() {
+        return ifExists;
+    }
+
+    public void setIfExists(boolean ifExists) {
+        this.ifExists = ifExists;
+    }
+
     public boolean isRemovePatiting() {
         return removePatiting;
     }

src/main/java/com/alibaba/druid/sql/dialect/postgresql/parser/PGSQLStatementParser.java

@@ -557,6 +557,10 @@ public class PGSQLStatementParser extends SQLStatementParser {
                     values.add(new SQLCharExpr(lexer.stringVal()));
                 } else if (lexer.token() == Token.LITERAL_INT) {
                     values.add(new SQLIdentifierExpr(lexer.numberString()));
+                } else if (lexer.identifierEquals(FnvHash.Constants.JSON_SET)
+                        || lexer.identifierEquals(FnvHash.Constants.JSONB_SET)) {
+                    SQLExpr json_set = this.exprParser.expr();
+                    values.add(json_set);
                 } else {
                     values.add(new SQLIdentifierExpr(lexer.stringVal()));
                 }

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

@@ -1763,6 +1763,13 @@ public class SQLStatementParser extends SQLParser {
             lexer.nextToken();
 
             SQLAlterTableStatement stmt = new SQLAlterTableStatement(getDbType());
+
+            if (lexer.token == Token.IF) {
+                lexer.nextToken();
+                accept(Token.EXISTS);
+                stmt.setIfExists(true);
+            }
+
             stmt.setName(this.exprParser.name());
 
             for (;;) {

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

@@ -5405,6 +5405,11 @@ public class SQLASTOutputVisitor extends SQLASTVisitorAdapter implements Paramet
     @Override
     public boolean visit(SQLAlterTableStatement x) {
         print0(ucase ? "ALTER TABLE " : "alter table ");
+
+        if (x.isIfExists()) {
+            print0(ucase ? "IF EXISTS " : "if exists ");
+        }
+
         printTableSourceExpr(x.getName());
         this.indentCount++;
         for (int i = 0; i < x.getItems().size(); ++i) {

src/main/java/com/alibaba/druid/util/FnvHash.java

@@ -1117,5 +1117,7 @@ public final class FnvHash {
         long RESTART = fnv1a_64_lower("RESTART");
 
         long ASOF = fnv1a_64_lower("ASOF");
+        long JSON_SET = fnv1a_64_lower("JSON_SET");
+        long JSONB_SET = fnv1a_64_lower("JSONB_SET");
     }
 }

src/test/java/com/alibaba/druid/bvt/sql/postgresql/PostgresqlResourceTest.java

@@ -52,6 +52,18 @@ public class PostgresqlResourceTest extends PGTest {
         exec_test("bvt/parser/postgresql-3.txt");
     }
 
+    public void test_4() throws Exception {
+        exec_test("bvt/parser/postgresql-4.txt");
+    }
+
+    public void test_5() throws Exception {
+        exec_test("bvt/parser/postgresql-5.txt");
+    }
+
+    public void test_6() throws Exception {
+        exec_test("bvt/parser/postgresql-6.txt");
+    }
+
     public void exec_test(String resource) throws Exception {
         System.out.println(resource);
         InputStream is = null;

src/test/resources/bvt/parser/hive-4.txt

@@ -0,0 +1,4 @@
+ALTER TABLE tb_a ADD COLUMNS ( a bigint );
+---------------------------
+ALTER TABLE tb_a
+	ADD COLUMNS (a bigint);

src/test/resources/bvt/parser/hive-5.txt

@@ -0,0 +1,4 @@
+INSERT INTO tb_a VALUES ( 1 );
+---------------------------
+INSERT INTO TABLE tb_a
+VALUES (1);

src/test/resources/bvt/parser/postgresql-4.txt

@@ -0,0 +1,20 @@
+SET data = jsonb_set(
+data,
+ARRAY[(
+SELECT idx - 1 AS idx
+FROM cgm_data c1,
+jsonb_array_elements(data)
+WHERE
+info ->> 'index' = ?
+and c1.id = ?
+)]::TEXT[],
+?::jsonb
+)
+WHERE t1.id = ?;
+---------------------------
+SET data TO jsonb_set(data, ARRAY[(
+	SELECT idx - 1 AS idx
+	FROM cgm_data c1, jsonb_array_elements(data)
+	WHERE info ->> 'index' = ?
+		AND c1.id = ?
+)]::TEXT[], ?::jsonb), t1, id, id

src/test/resources/bvt/parser/postgresql-5.txt

@@ -0,0 +1,5 @@
+select * from com_demo order by sex asc nulls first
+---------------------------
+SELECT *
+FROM com_demo
+ORDER BY sex ASC NULLS FIRST

src/test/resources/bvt/parser/postgresql-6.txt

@@ -0,0 +1,5 @@
+alter table if exists tcweatherdata
+add column predictiontime timestamp
+---------------------------
+ALTER TABLE IF EXISTS tcweatherdata
+	ADD COLUMN predictiontime timestamp