I have a user table like this, name week_no year_no fb 5 2021 twitter 1 2022 twitter 2 2022 twitter 3 2022 twitter 7 2022 youtube 21 2022 I want to find the names of users who login >= 3…
Description: We have two tables as below: table_1 ("question" main table) table_2 ("question_attempted" joining table) Cases: In "table_2" we have a column that has a column "is_correct" (holds 1,0) for right or wrong answers. In "table_1" we have 1 m…
Run into sql code with a lot of when: case when callDuration > 0 and callDuration < 30 then 1.4 when callDuration >= 30 and callDuration < 60 then 2.3 when callDuration >= 60 and callDuration < 120 then 3.7…
i have a chat website and i want the user to have a list available of users sorted by who they last chatted with(like whatsapp). how do i do this? i tried many stack overflow answers but none of them…
On running the following MySQL (5.7.12) UPDATE statement, I get the error "Error Code: 1054. Unknown column 't1.col2' in 'where clause'". How can I rephrase this query such that the columns of t1 are accessible in the subquery? UPDATE MyFirstTable…
Still learning sql, but I'm not understanding how all the data I'm putting in my tables are set to 0 or NULL ?
I have a DETAILS table having detail_id, customer_id and type columns. type can either be 'A' or 'B'. customer can have both type. Goal is to find customer of Type B ONLY. i.e output should not give customer details having…
I'm having trouble understanding my options for how to optimize this specific query. Looking online, I find various resources, but all for queries that don't match my particular one. From what I could gather, it's very hard to optimize a…
I have 2 tables tableA: id dateA colA ... 1 2022-11-11 12:00:00 A 2 2022-11-12 12:00:00 B 3 2022-11-14 12:00:00 C tableB: id dateB colB ... 3 2022-11-05 12:00:00 D 4 2022-11-06 12:00:00 E 5 2022-11-13 12:00:00 F and I…
TL;DR (i.e. asking the question first): Is there any way to write an INSERT INTO...SELECT FROM...GROUP BY...ON DUPLICATE KEY UPDATE statement using row alias(es) in the ON DUPLICATE KEY UPDATE clause instead of the col1 = VALUES(col1) syntax that has…