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Tag: subquery

put on duplicate key update in MySQL

let’s say i have 2 tables table shipping id origin order_id createdAt product_id amount 1 1 11 2020-12-22 234 2000 2 1 11 2020-12-22 235 3000 3 1 11 2020-12-22 236 4000 4 2 12 2020-12-22 236 3000 5 2 12 2020-12-22 235 2100 6 3 13 2020-12-22 236 2200 7 3 13 2020-12-22 239 3400 8 4 14 2020-12-22

subquery shows more that one row group by

I am trying to get the data for the best 5 customers in a railway reservation system. To get that, I tried getting the max value by summing up their fare every time they make a reservation. Here is the code. this throws the error:[21000][1242] Subquery returns more than 1 row If I remove the group by from the…

Select max date per year

I have the table as follows: And I’d like to select the max date for every year per user, so the result would be like: Some help? Thank you! Answer Just use aggregation: If you have more columns that you want, then use distinct on: