Category Archives: oracle

What is ETL in Sql ?

What is ETL: ETL stands for Extract, Transform, Load. Extract means to read data from source, Transform means to apply business logic on data & in last load means to add or load data on other server. ETL (Extract, Transform … Continue reading

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How do I find duplicate values in a table in Oracle?

To find duplicate value we need the sql group by & having clause as below. SELECT V.FIELD_NAME1, COUNT(*) FROM TABLE_NAME V GROUP BY V.FIELD_NAME1 HAVING COUNT(*)>1 How query works? First it will group the same value by non-clustered index i.e. virtual … Continue reading

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What is clustered & non-clustered index in oracle?

Clustered index & Non-clustered index A clustered index the table records are physically stored on the basic of that index, A table can have only one clustered index because of physically stored to the table. A Non-clustered index that is … Continue reading

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How to get table size in MB oracle ?

select segment_name,segment_type,bytes/1024/1024 MB from dba_segments where segment_type=’TABLE’ and lower(segment_name)=’your_table_name’;

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what is difference between oracle & mysql ?

Key difference: The Oracle Database is an object-relational database management system (ORDBMS). MySQL is an open source relational database management system (RDBMS). MySQL is the world’s most used RDBMS, and runs as a server providing multi-user access to a number … Continue reading

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