Sql – How to read an attribute of the XML

sqlxquery

DECLARE @XmlData xml
SET @XmlData= '<?xml version="1.0" encoding="utf-8" ?>
<ROOT PROCESS_DATE="25-Nov-2009" ROW_COUNT="2" VERIFY_TOTAL="654454.54">
    <row rowNumber="1">
        <Code1>11111</Code1>
        <Code2>AAAA </Code2>
    </row>
    <row rowNumber="2">
        <Code1>2222</Code1>
        <Code2>BBBB </Code2>
    </row>
</ROOT>'

-- Following query returns the Code1, & Code2 for each row.  
SELECT 
                R.i.query('Code1').value('.', 'nvarchar(8)') AS Code1,
                R.i.query('Code2').value('.', 'nvarchar(8)') AS Code2
FROM @XmlData.nodes('/ROOT/row') R(i)

-- Now I want to get the rowNumber attribute of each row in the resultset.
SELECT 
                R.i.query('@rowNumber') AS rowNumber,
                R.i.query('Code1').value('.', 'nvarchar(8)') AS Code1,
                R.i.query('Code2').value('.', 'nvarchar(8)') AS Code2
FROM @XmlData.nodes('/ROOT/row') R(i)

-- Above query returns error

Best Answer

DECLARE @x XML ;
SET @x = '<?xml version="1.0" encoding="utf-8" ?>
<ROOT PROCESS_DATE="25-Nov-2009" ROW_COUNT="2" VERIFY_TOTAL="654454.54">
    <row rowNumber="1">
        <Code1>11111</Code1>
        <Code2>AAAA </Code2>
    </row>
    <row rowNumber="2">
        <Code1>2222</Code1>
        <Code2>BBBB </Code2>
    </row>
</ROOT>' ;

SELECT  v.value('.', 'VARCHAR(20)') AS Name
FROM    @x.nodes('(/ROOT/row/@*)') x ( v )

Related Solutions

Sql – the difference between “INNER JOIN” and “OUTER JOIN”

Assuming you're joining on columns with no duplicates, which is a very common case:

An inner join of A and B gives the result of A intersect B, i.e. the inner part of a Venn diagram intersection.
An outer join of A and B gives the results of A union B, i.e. the outer parts of a Venn diagram union.

Examples

Suppose you have two tables, with a single column each, and data as follows:

Note that (1,2) are unique to A, (3,4) are common, and (5,6) are unique to B.

Inner join

An inner join using either of the equivalent queries gives the intersection of the two tables, i.e. the two rows they have in common.

select * from a INNER JOIN b on a.a = b.b;
select a.*, b.*  from a,b where a.a = b.b;

a | b
--+--
3 | 3
4 | 4

Left outer join

A left outer join will give all rows in A, plus any common rows in B.

select * from a LEFT OUTER JOIN b on a.a = b.b;
select a.*, b.*  from a,b where a.a = b.b(+);

a |  b
--+-----
1 | null
2 | null
3 |    3
4 |    4

Right outer join

A right outer join will give all rows in B, plus any common rows in A.

select * from a RIGHT OUTER JOIN b on a.a = b.b;
select a.*, b.*  from a,b where a.a(+) = b.b;

a    |  b
-----+----
3    |  3
4    |  4
null |  5
null |  6

Full outer join

A full outer join will give you the union of A and B, i.e. all the rows in A and all the rows in B. If something in A doesn't have a corresponding datum in B, then the B portion is null, and vice versa.

select * from a FULL OUTER JOIN b on a.a = b.b;

 a   |  b
-----+-----
   1 | null
   2 | null
   3 |    3
   4 |    4
null |    6
null |    5

Sql – the difference between UNION and UNION ALL

UNION removes duplicate records (where all columns in the results are the same), UNION ALL does not.

There is a performance hit when using UNION instead of UNION ALL, since the database server must do additional work to remove the duplicate rows, but usually you do not want the duplicates (especially when developing reports).

To identify duplicates, records must be comparable types as well as compatible types. This will depend on the SQL system. For example the system may truncate all long text fields to make short text fields for comparison (MS Jet), or may refuse to compare binary fields (ORACLE)

UNION Example:

SELECT 'foo' AS bar UNION SELECT 'foo' AS bar

Result:

+-----+
| bar |
+-----+
| foo |
+-----+
1 row in set (0.00 sec)

UNION ALL example:

SELECT 'foo' AS bar UNION ALL SELECT 'foo' AS bar