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I was interviewed before Feb 2024.
Using PIVOT in SQL to transform input table into expected output
Use the PIVOT keyword followed by the aggregation function and column to pivot on
Specify the values to pivot on as columns in the output table
Include the FOR clause to specify the values to pivot on
Example: SELECT * FROM input_table PIVOT (SUM(value) FOR category IN ('A', 'B', 'C')) AS output_table
Incremental load process flow involves identifying new/updated data, extracting, transforming, and loading it into the target system.
Identify the source data that has changed since the last load
Extract only the new/updated data from the source system
Transform the data as needed (e.g. applying business rules, data cleansing)
Load the transformed data into the target system, either appending to existing data or updating e
Query optimization involves steps to improve the performance of database queries.
Identify slow queries using tools like query logs or profiling.
Analyze query execution plans to understand how queries are being processed.
Optimize queries by adding indexes, rewriting queries, or restructuring data.
Consider factors like data distribution, join types, and query complexity.
Test and benchmark optimized queries to ensure perf
SCD Type 2 is used to track historical changes in data by creating new records for changes.
Identify changes in source data
Insert new record with updated data
Update end date of previous record
Add post commands like updating flags or triggers
Example: If a customer changes their address, a new record is created with the updated address while the previous record is marked as expired.
Dimension tables store descriptive attributes while fact tables store quantitative data. Dimension tables are loaded first.
Dimension tables contain attributes like customer name, product category, etc.
Fact tables contain quantitative data like sales revenue, quantity sold, etc.
Dimension tables are typically loaded first as they provide context for the quantitative data in fact tables.
I applied via Job Portal and was interviewed in Mar 2024. There was 1 interview round.
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I applied via Campus Placement and was interviewed before Jan 2022. There were 4 interview rounds.
It's an assignment for apti, verbal
I applied via Naukri.com and was interviewed in Mar 2022. There was 1 interview round.
I applied via Naukri.com and was interviewed in Dec 2023. There was 1 interview round.
ETL is Extract, Transform, Load where data is extracted, transformed, and loaded into a data warehouse. ELT is Extract, Load, Transform where data is extracted, loaded into a data warehouse, and then transformed.
ETL involves extracting data from source systems, transforming it according to business rules, and loading it into a data warehouse.
ELT involves extracting data from source systems, loading it into a data wareh...
Loads in Informatica refer to the process of moving data from source to target in a data warehouse.
Loads involve extracting data from source systems
Transforming the data as needed
Loading the data into the target data warehouse or database
Loads can be full, incremental, or delta depending on the requirements
Example: Loading customer data from a CRM system into a data warehouse for analysis
Use GROUP BY and HAVING clause to find duplicates in a table.
Use GROUP BY to group rows with same values together
Use HAVING COUNT(*) > 1 to filter out duplicates
Example: SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name HAVING COUNT(*) > 1;
I applied via Campus Placement and was interviewed before Oct 2023. There was 1 interview round.
I applied via Naukri.com and was interviewed before Aug 2022. There were 3 interview rounds.
I applied via Naukri.com and was interviewed before Apr 2023. There was 1 interview round.
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