SQL Window Functions Series: LAG() and LEAD()
Dive deep into the powerful SQL window functions, LAG() and LEAD(). Explore their intricacies, discover real-world examples, and avoid common pitfalls.
2023-12-11
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LAG
2022-06-17
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2021-03-02
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2021-02-23
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Question of the Day
STRING_AGG's behavior
Executing the following script (Sql Server 2022), you get the table t0 with 10 rows:
CREATE TABLE t0
( id INT PRIMARY KEY
, field1 VARCHAR(1000)
, field2 VARCHAR(MAX));
INSERT INTO t0
SELECT
gs.value
, REPLICATE ('X', 1000)
, REPLICATE ('Y', 1000)
FROM generate_series(1, 10, 1) gs;
GOWhat happens if you execute the following statements?
select STRING_AGG(field1, ';') within group (order by id) from t0;
select STRING_AGG(field2, ';') within group (order by id) from t0;