Oracle Sql Rowid

SQL statement for querying and deleting duplicate records (i) For example, there is a field "name" in Table A, and the "name" value may be the same between different records, and now you need to query between the records in the table, the "name" value has duplicates, and select name, Count (*) from-a group by name has count (*) > 1 as ...

Method 1 delete yourtable where [id] not in (select max ([id]) from yourtable group by (name + value) b on a.id = b.id where b.id ...

We want to do not only write SQL, but also to do a good performance of the SQL, the following for the author to learn, extract, and summarized part of the information to share with you! (1) Select the most efficient table name order (valid only in the Rule-based optimizer): The ORACLE parser processes the table names in the FROM clause in Right-to-left order, and the last table in the FROM clause (the underlying table driving tables) is processed first, In the case where multiple tables are included in the FROM clause, you must select the table with the least number of records as the underlying table. If...

Logminer is an actual, useful analysis tool that Oracle has provided since 8i, which makes it easy to obtain specific content in Oracle Redo log files (archived log files), Logminer analysis tools are actually made up of a set of PL SQL package and a number of dynamic views that can be used to analyze online logs and archive logs to obtain a database of past detailed, specific operations, very useful. Why do you use Logminer? Mainly for the following reasons: When the database has been mistakenly operated, need not be completed ...

Logminer is an actual, useful analysis tool that Oracle has provided since 8i, which makes it easy to obtain specific content in Oracle Redo log files (archived log files), Logminer analysis tools are actually made up of a set of PL 　　SQL package and a number of dynamic views that can be used to analyze online logs and archive logs to obtain a database of past detailed, specific operations, very useful. 　　Why do you use Logminer? Mainly for the following reasons: When the database occurs ...