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Tag: mysql

number of appearances of an atribute before a date in a query

I have this table and what I need as an output is to have for each payment the number of payments that have been done with the same credit card. For example, for the first payment there would be 0 payments with the same credit card. for the second payment there would be 1 payment with the same credit card.

How to get Table field names at top of result array

Here is my Sample table: Here is My Query: Result for above query is: I need to get the field names in the first element of the array. Expected result array is: How can I modify the Query to get this result? Thanks in advance… Answer Display issues should generally be dealt with in application code, not SQL queries. If

how to comparison LAG function in mysql

I got complicated problem in mysql. I have some table on mydatabase. sample docs(this is only simple sample, actual data are so many table that I have to join) table “merchant” table “transaction” I want to know the information of merchants transaction daily “before” and “after” to comparison like this below I tried with this query but that query didn’t

I need to optimize tables and queries

I have 3 tables: info, data, link, there is a request for data: offer optimization options: a) tables b) request. Queries for creating tables: Thanks! Answer Never use commas in the FROM clause. Always use proper, explicit, standard, readable JOIN syntax: Second, for this query your indexes are probably fine. I would also recommend a primary key index on link:

Foreign Key on MySQL

I am new to SQL and I started building my own project. I am having issues creating a foreign key on my second table. . Please let me know what I am missing here. Answer The second CREATE TABLE statement should be:

How to take union and write into the same table?

I have a table A with columns (x, y, z) and I have another table B with columns (x, y, z), basically the same schema. I want to add those rows from B into A, which do not already exist in A, basically after the operation the union of A and B exist in table A. How do I do

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