MariaDB 10.6

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CREATE TABLE valuation(ticker TEXT,
depot_id INT
,src_id INT
,valuation_date DATE,
value DECIMAL(10,2)
)
INSERT INTO valuation (ticker,depot_id,src_id,valuation_date,value)
SELECT 'BK001EUR',1,2,'2009-09-09',14999260.46
WHERE NOT EXISTS (SELECT 1 
                  FROM valuation 
                   WHERE ticker = 'BK001EUR' 
                     AND depot_id =1 
                     AND src_id =2 AND valuation_date ='2009-09-09');

Records: 1  Duplicates: 0  Warnings: 0


SELECT * FROM valuation


ticker
depot_id
src_id
valuation_date
value


BK001EUR
1
2
2009-09-09
14999260.46


INSERT INTO valuation (ticker,depot_id,src_id,valuation_date,value)
SELECT 'BK001EUR',1,2,'2009-09-09',14999260.46
WHERE NOT EXISTS (SELECT 1 
                  FROM valuation 
                   WHERE ticker = 'BK001EUR' 
                     AND depot_id =1 
                     AND src_id =2 AND valuation_date ='2009-09-09');

Records: 0  Duplicates: 0  Warnings: 0


SELECT * FROM valuation


ticker
depot_id
src_id
valuation_date
value


BK001EUR
1
2
2009-09-09
14999260.46