MySql:
UPDATE TableA
INNER JOIN tableB ON TableA.ITEMNO = tableB.ITEMNO
SET TableA.column1 = tableB.column1,
 TableA.STATUS = IFNULL(
    tableB.ITEMSTATUS,
    'ITEMSTATUS'
)
WHERE
    ID = 'ID'
AND IFNULL(TableA.ITEMNO, '') <> ''
AND IFNULL(TableA.column1, '') = ''Sql Server:
UPDATE TableA
SET TableA.column1 = tableB.column1,
 TableA. STATUS = ISNULL(
    tableB.ITEMSTATUS ,'ITEMSTATUS'
)
FROM
    TableA
INNER JOIN tableB ON TableA.ITEMNO = tableB.ITEMNO
WHERE
    ID ='ID'
AND ISNULL(TableA.ITEMNO, '') <> ''
AND ISNULL(TableA.column1, '') = ''- 12
 
下面是MySql更新语法 
 1、单表的UPDATE语句
UPDATE [LOW_PRIORITY] [IGNORE] tbl_name
SET col_name1=expr1 [, col_name2=expr2 ...]
[WHERE where_definition]
[ORDER BY ...]
[LIMIT row_count]- 1
 - 2
 - 3
 - 4
 - 5
 
2、多表的UPDATE语句
UPDATE [LOW_PRIORITY] [IGNORE] table_references
SET col_name1=expr1 [, col_name2=expr2 ...]
[WHERE where_definition]- 1
 - 2
 - 3
 
作者:jiankunking 出处:http://blog.csdn.net/jiankunking

                

















