This parameter is used in conjunction with TABLE parameter of exp (export) utility of Oracle. This parameter will enable selection of rows from the list of tables mentioned in TABLE parameter. The value to this parameter is a WHERE clause for a SELECT statement which you would normally issue.
For example if you want to query all records of employees for a particular department you will use:
SELECT *
FROM employees
WHERE dept = 10;
To export these rows into a file using exp utility you will follow the below syntax:
exp scott/tiger TABLES=employees QUERY=\"WHERE dept=10\"
Use \ for providing character or special characters like less than or greater than symbol inside the string. Also for operating system keywords you need to place \ as escape character.
For example:
exp scott/tiger TABLES=employees QUERY=\"WHERE name=\ANANTHA\' and sal \<1600\" The default value for QUERY parameter is NULL. Note: If there are multiple tables in TABLES parameter, this QUERY will be applied to all those tables.
You can also use ROWID for exporting, for example:
exp scott/tiger@slspnc1 tables=emp query=\"where ROWID='AAAMgzAAEAAAAAgAAB'\" file=test.dmp log=test.log
In Windows it is not required to put escape character for single quote character wheras you need to put escape character if you are using Linux or its variants.
exp scott/tiger@slspnc1 tables=emp query=\"where ROWID=\'AAAMgzAAEAAAAAgAAB\'\" file=test.dmp log=test.log
Restrictions When Using the QUERY Parameter:
The QUERY parameter cannot be specified for full, user, or tablespace-mode exports.
The QUERY parameter must be applicable to all specified tables.
The QUERY parameter cannot be specified in a direct path Export (DIRECT=y)
The QUERY parameter cannot be specified for tables with inner nested tables.
You cannot determine from the contents of the export file whether the data is the result of a QUERY export.
