I’m trying to select random strings. The problem is it returns the same value for each row. Why is that and how to fix? 10 rows Answer Postgres overoptimizes the subquery. I think this is an error, because it is missing the fact that random() is volatile. A simple fix is a correlation clause: I rewrote the logic a bit,
Tag: postgresql
Case when date = current_date then text
I have a table like this: But when I execute this query: I get this result: SQL Fiddle I would expect that in the rows where is_equal is true, the result should be TODAY. What am I doing wrong? Answer Nevermind, I solved it, but I don’t want to discard the question. The solution is to CAST(token_date as varchar) in
How to make separately unique each column in postgresql?
I know we can apply primary key to a column to provide uniqueness for a row and we can apply multiple primary keys and get a composite key. But this didn’t work for my case. I have userID and email columns. And I want them to be unique at the same time. When I applied primary key attribute to both
JPA Batch inserts with non auto generated id
im triying to batch insert a few Million Entitys. The Batch insert kind of works, but my programm executes a few JDBC Statements in the background which i dont want. } my Repository: my Entity: my JPA Settings: The Batch Insert Does work, but if i try to Upload 100 Entitys i have 33 JDBC Statements which are checking the
How to transpose column to row and duplicate the original column header?
I have a table for example as below, the alphabet is header and the numbers are its records a b c d e f ——————— 3 4 5 6 2 3 5 3 2 9 8 7 I want to …
Check constraint before insert a value into the database
I’m trying to create a table to store order_details. The table has a column status that should only be allowed to contain the value true once per each order_id, but may contain the value false multiple times per order_id. I want to do this within the table structure itself. Any help would be appreciated. Thanks in advance. Answer You can
How to select count of 0s, 1s, and both 0s and 1s in a postgres table column?
Say there’s a table that has columns named binary_value, name, and created_at along with the id column. Here’s the SQL Fiddle for this question: http://sqlfiddle.com/#!15/d15d1/36 What would be an efficient query to get a result like the following? So far, I’ve got: Which gives it in column form: How can we get the result in a row? Perhaps there’s a
How to check if two columns are consistent in a table. sql
I’m struggling to ask the question so I will just put an example table. Basically, if I have two columns with headings person and insured car, how can I check if the same person consistently insures the same brand of car. So basically in this table I want to filter out person 0 because he insures both Toyota’s and Mazda’s,
Find the row violating the constraint to be added
I’m trying to add a check constraint to a table like ALTER TABLE foo ADD CONSTRAINT bar CHECK (…); and I get the error: ERROR: check constraint “bar” is violated by some row ********** Error ****…
SQL : IN operator vs multiple ORs
There is a behaviour I would like to understand for good. Query #1: Output : 504 Query #2 Output : 87 Query #3 Output : 0 I want to understand why am I getting zero in the third query. Based on this, the ( , ) is equivalent to a multiple OR. Isn’t this OR inclusive ? Answer the (