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https://issues.apache.org/jira/browse/HIVE-9580?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14496785#comment-14496785
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Aihua Xu commented on HIVE-9580:
--------------------------------
That's right. For the key comparison, it will call UDF to do the key conversion
if we are comparing different types, or I think we should pick the common type
as the key type if the type conversion is not needed for the data types
including char or varchar with different lengths.
> Server returns incorrect result from JOIN ON VARCHAR columns
> ------------------------------------------------------------
>
> Key: HIVE-9580
> URL: https://issues.apache.org/jira/browse/HIVE-9580
> Project: Hive
> Issue Type: Bug
> Components: HiveServer2
> Affects Versions: 0.12.0, 0.13.0, 0.14.0
> Reporter: Mike
> Assignee: Aihua Xu
> Attachments: HIVE-9580.patch
>
>
> The database erroneously returns rows when joining two tables which each
> contain a VARCHAR column and the join's ON condition uses the equality
> operator on the VARCHAR columns.
> ******The following JDBC method exhibits the problem:
> static void joinIssue()
> throws SQLException {
>
> String sql;
> int rowsAffected;
> ResultSet rs;
> Statement stmt = con.createStatement();
> String table1_Name = "blahtab1";
> String table1A_Name = "blahtab1A";
> String table1B_Name = "blahtab1B";
> String table2_Name = "blahtab2";
>
> try {
> sql = "drop table " + table1_Name;
> System.out.println("\nsql=" + sql);
> rowsAffected = stmt.executeUpdate(sql);
> }
> catch (SQLException se) {
> println("Drop table error:" + se.getMessage());
> }
> try {
> sql = "CREATE TABLE " + table1_Name + "(" +
> "VCHARCOL VARCHAR(10) " +
> ",INTEGERCOL INT " +
> ") "
> ;
> System.out.println("\nsql=" + sql);
> rowsAffected = stmt.executeUpdate(sql);
> }
> catch (SQLException se) {
> println("create table error:" + se.getMessage());
> }
>
> sql = "insert into " + table1_Name + " values ('jklmnopqrs',
> 99)";
> System.out.println("\nsql=" + sql);
> stmt.executeUpdate(sql);
>
>
> System.out.println("=======================================================================================================================================");
>
> try {
> sql = "drop table " + table1A_Name;
> System.out.println("\nsql=" + sql);
> rowsAffected = stmt.executeUpdate(sql);
> }
> catch (SQLException se) {
> println("Drop table error:" + se.getMessage());
> }
> try {
> sql = "CREATE TABLE " + table1A_Name + "(" +
> "VCHARCOL VARCHAR(10) " +
> ") "
> ;
> System.out.println("\nsql=" + sql);
> rowsAffected = stmt.executeUpdate(sql);
> }
> catch (SQLException se) {
> println("create table error:" + se.getMessage());
> }
>
> sql = "insert into " + table1A_Name + " values ('jklmnopqrs')";
> System.out.println("\nsql=" + sql);
> stmt.executeUpdate(sql);
>
> System.out.println("=======================================================================================================================================");
>
> try {
> sql = "drop table " + table1B_Name;
> System.out.println("\nsql=" + sql);
> rowsAffected = stmt.executeUpdate(sql);
> }
> catch (SQLException se) {
> println("Drop table error:" + se.getMessage());
> }
> try {
> sql = "CREATE TABLE " + table1B_Name + "(" +
> "VCHARCOL VARCHAR(11) " +
> ",INTEGERCOL INT " +
> ") "
> ;
> System.out.println("\nsql=" + sql);
> rowsAffected = stmt.executeUpdate(sql);
> }
> catch (SQLException se) {
> println("create table error:" + se.getMessage());
> }
>
> sql = "insert into " + table1B_Name + " values ('jklmnopqrs',
> 99)";
> System.out.println("\nsql=" + sql);
> stmt.executeUpdate(sql);
>
>
> System.out.println("=======================================================================================================================================");
>
> try {
> sql = "drop table " + table2_Name;
> System.out.println("\nsql=" + sql);
> rowsAffected = stmt.executeUpdate(sql);
> }
> catch (SQLException se) {
> println("Drop table error:" + se.getMessage());
> }
> try {
> sql = "CREATE TABLE " + table2_Name + "(" +
> "VCHARCOL VARCHAR(30) " +
> ") "
> ;
> System.out.println("\nsql=" + sql);
> rowsAffected = stmt.executeUpdate(sql);
> }
> catch (SQLException se) {
> println("create table error:" + se.getMessage());
> }
> sql = "insert into " + table2_Name + " values ('jklmnopqrsX')";
> System.out.println("\nsql=" + sql);
> stmt.executeUpdate(sql);
>
>
> System.out.println("=======================================================================================================================================");
>
> sql = "select * from " + table1_Name;
> System.out.println("\nsql=" + sql);
> rs = stmt.executeQuery(sql);
> dispResultSet(rs, true, true);
>
> System.out.println("=======================================================================================================================================");
> sql = "select * from " + table1A_Name;
> System.out.println("\nsql=" + sql);
> rs = stmt.executeQuery(sql);
> dispResultSet(rs, true, true);
>
>
> System.out.println("=======================================================================================================================================");
> sql = "select * from " + table1B_Name;
> System.out.println("\nsql=" + sql);
> rs = stmt.executeQuery(sql);
> dispResultSet(rs, true, true);
>
> System.out.println("=======================================================================================================================================");
>
> sql = "select * from " + table2_Name;
> System.out.println("\nsql=" + sql);
> rs = stmt.executeQuery(sql);
> dispResultSet(rs, true, true);
>
> System.out.println("=======================================================================================================================================");
>
> sql = "SELECT " +
> table1_Name + ".VCHARCOL, " +
> table2_Name + ".VCHARCOL " +
> "FROM " + table1_Name + " JOIN " + table2_Name
> +
> " ON (" + table1_Name + ".VCHARCOL = "
> + table2_Name + ".VCHARCOL)";
> System.out.println("\nsql=" + sql);
> rs = stmt.executeQuery(sql);
> dispResultSet(rs, true, true);
>
> System.out.println("=======================================================================================================================================");
>
> sql = "SELECT " +
> table1_Name + ".VCHARCOL, " +
> table2_Name + ".VCHARCOL " +
> "FROM " + table2_Name + " JOIN " + table1_Name
> +
> " ON (" + table2_Name + ".VCHARCOL = "
> + table1_Name + ".VCHARCOL)";
> System.out.println("\nsql=" + sql);
> rs = stmt.executeQuery(sql);
> dispResultSet(rs, true, true);
>
>
> System.out.println("=======================================================================================================================================");
>
> sql = "SELECT " +
> table1A_Name + ".VCHARCOL, " +
> table2_Name + ".VCHARCOL " +
> "FROM " + table1A_Name + " JOIN " + table2_Name
> +
> " ON (" + table1A_Name + ".VCHARCOL = "
> + table2_Name + ".VCHARCOL)";
> System.out.println("\nsql=" + sql);
> rs = stmt.executeQuery(sql);
> dispResultSet(rs, true, true);
>
> System.out.println("=======================================================================================================================================");
>
> sql = "SELECT " +
> table1B_Name + ".VCHARCOL, " +
> table2_Name + ".VCHARCOL " +
> "FROM " + table1B_Name + " JOIN " + table2_Name
> +
> " ON (" + table1B_Name + ".VCHARCOL = "
> + table2_Name + ".VCHARCOL)";
> System.out.println("\nsql=" + sql);
> rs = stmt.executeQuery(sql);
> dispResultSet(rs, true, true);
>
> stmt.close();
> }
> ******The output generated by program run is as follows (for 0.13):
> sql=drop table blahtab1
> sql=CREATE TABLE blahtab1(VCHARCOL VARCHAR(10) ,INTEGERCOL INT )
> sql=insert into blahtab1 values ('jklmnopqrs', 99)
> =======================================================================================================================================
> sql=drop table blahtab1A
> sql=CREATE TABLE blahtab1A(VCHARCOL VARCHAR(10) )
> sql=insert into blahtab1A values ('jklmnopqrs')
> =======================================================================================================================================
> sql=drop table blahtab1B
> sql=CREATE TABLE blahtab1B(VCHARCOL VARCHAR(11) ,INTEGERCOL INT )
> sql=insert into blahtab1B values ('jklmnopqrs', 99)
> =======================================================================================================================================
> sql=drop table blahtab2
> sql=CREATE TABLE blahtab2(VCHARCOL VARCHAR(30) )
> sql=insert into blahtab2 values ('jklmnopqrsX')
> =======================================================================================================================================
> sql=select * from blahtab1
> vcharcol(10):jklmnopqrs|integercol(10):99|
> Num rows in result set = 1
> =======================================================================================================================================
> sql=select * from blahtab1A
> vcharcol(10):jklmnopqrs|
> Num rows in result set = 1
> =======================================================================================================================================
> sql=select * from blahtab1B
> vcharcol(11):jklmnopqrs|integercol(10):99|
> Num rows in result set = 1
> =======================================================================================================================================
> sql=select * from blahtab2
> vcharcol(30):jklmnopqrsX|
> Num rows in result set = 1
> =======================================================================================================================================
> sql=SELECT blahtab1.VCHARCOL, blahtab2.VCHARCOL FROM blahtab1 JOIN blahtab2
> ON (blahtab1.VCHARCOL = blahtab2.VCHARCOL)
> vcharcol(10):jklmnopqrs|vcharcol(30):jklmnopqrsX|
> Num rows in result set = 1
> =======================================================================================================================================
> sql=SELECT blahtab1.VCHARCOL, blahtab2.VCHARCOL FROM blahtab2 JOIN blahtab1
> ON (blahtab2.VCHARCOL = blahtab1.VCHARCOL)
> Num rows in result set = 0
> =======================================================================================================================================
> sql=SELECT blahtab1A.VCHARCOL, blahtab2.VCHARCOL FROM blahtab1A JOIN blahtab2
> ON (blahtab1A.VCHARCOL = blahtab2.VCHARCOL)
> Num rows in result set = 0
> =======================================================================================================================================
> sql=SELECT blahtab1B.VCHARCOL, blahtab2.VCHARCOL FROM blahtab1B JOIN blahtab2
> ON (blahtab1B.VCHARCOL = blahtab2.VCHARCOL)
> Num rows in result set = 0
> ******The server should NOT return any rows for the following query, but it
> does:
> SELECT blahtab1.VCHARCOL, blahtab2.VCHARCOL FROM blahtab1 JOIN blahtab2 ON
> (blahtab1.VCHARCOL = blahtab2.VCHARCOL)
> Result:
> vcharcol(10):jklmnopqrs|vcharcol(30):jklmnopqrsX|
> Num rows in result set = 1
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