Constantin Lungu – Medium

Constantin Lungu

Published in

Using LAST_VALUE with STRUCTS

Even an “empty” STRUCT is still technically something. Not the same as a standalone NULL value.

Oct 5

Using LAST_VALUE with STRUCTS

Oct 5

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Table grain quick validation with SQL

I was doing some exploratory data analysis on a number of tables I didn’t have much information about and, unfortunately, didn’t know their…

Oct 4

Table grain quick validation with SQL

Oct 4

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WITH expressions in BigQuery

So I recently discovered the WITH expression in BigQuery SQL.

Sep 30

WITH expressions in BigQuery

Sep 30

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Beware of ROW_NUMBER without ORDER BY

Haven’t posted all summer, but this bug pulled me straight out of the shadows.

Sep 30

Beware of ROW_NUMBER without ORDER BY

Sep 30

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Aggregating Multiple SCD-2 Attribute Timelines in BigQuery

Here’s another practical BigQuery SQL exercise 💡

Jun 11

Aggregating Multiple SCD-2 Attribute Timelines in BigQuery

Jun 11

Published in

Cross-dataset foreign key relationships in BigQuery

It turns out you can now (don’t know since when though) create cross-dataset foreign key relationships in BigQuery hashtag#SQL. Previously…

Jun 9

Cross-dataset foreign key relationships in BigQuery

Jun 9

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Why you should think twice before UNNESTing arrays or date intervals

If you ever work with terabyte-scale data, try to avoid unnecessary unnesting/unpacking arrays and date ranges. If you have no choice…

Jun 9

Why you should think twice before UNNESTing arrays or date intervals

Jun 9

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Compacting date intervals in BigQuery

Here’s a practical BigQuery SQL exercise that highlights some important concepts as well is an interesting algorithm imho. I’ve pair…

Jun 9

Compacting date intervals in BigQuery

Jun 9

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Null-safe comparison: IS DISTINCT/NOT DISTINCT FROM

I’ve been working for surprisingly long with SQL to have found this only a few days ago. Not long enough I guess 🤓.

May 6

Null-safe comparison: IS DISTINCT/NOT DISTINCT FROM

May 6

Published in

Transforming cumulative sums into monthly values

Here’s a quick BigQuery SQL exercise. I often work with cumulative aggregations, but it’s not every day that I need to reverse…

Mar 27

Transforming cumulative sums into monthly values

Mar 27

Constantin Lungu

Constantin Lungu

Software Engineer with a focus on Analytics — Data Engineering, Data Science & Business Intelligence | Opinions are my own

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