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0
votes
2answers
40 views

mysql table replication on just some records?

I have a big database which contain a table with about 26 million records. Now i need to make some reports on it from a special period of time. So how to make a replication from that table from a ...
6
votes
3answers
183 views

Convert date in date list condition to list of date ranges

I want to look for all the records that occur on specific dates. SELECT * FROM table1 WHERE date(column) in ($date1, $date2, ...); However, as many of you, know this kind of comparison doesn't get ...
0
votes
1answer
38 views

Calculations involving thresholds between two tables

I have a table comment and a table price like below. The key columns in both tables are ticker_id, price_datetime and price_open. The last column threshold in table comment (which currently NULL) is ...
1
vote
1answer
187 views

Change constraint on column based on value of another

Is it possible to change a constraint on a column in postgres based on the value of another column? E.g. (pseudocode): CREATE TABLE transactions( id SERIAL PRIMARY KEY, type TXN_TYPE NOT ...
1
vote
1answer
253 views

Select two aggregate functions on the same column using different criteria - performance

Dear stack exchange users, first question here. The database in question is a service database where a user hires a service. Now I would like to show the person that was hired an overview of how many ...
0
votes
1answer
1k views

Use if exists in postgresql [closed]

I know about the exists feature, but that does not help me with the given situation. What I want is: Check if some row exists, and if exists then check for an another row if row exists. Here's ...
1
vote
1answer
379 views

How to conditionally raise an error in MySQL without stored procedure

I need to conditionally raise an error, but I can only use a simple statement and no stored procedure. I'd like to do something like this: select case when foo = "bar" then 1 else SIGNAL SQLSTATE ...
1
vote
4answers
44 views

where clause: if this value from col x make sure col y is this value

I feel like this is an easy one for you Experts! I haven't done any kind of Advanced SQL in years. Fundamental question: select * from myTable where ((if col1 = 'this', make sure col2 = ...
2
votes
1answer
93 views

Conditionally join table

I'm new to database design and have designed a database that seems fine for the application but looks like it has a major red flag to me. I have a master table which is then joined to another table ...
1
vote
1answer
117 views

MYSQL testing string field contains another altered string field

I have this table : mysql> desc mytab; +------------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | ...
0
votes
2answers
58 views

Oracle conditional statements

I am making a report, and I am trying to do following: If the value of the field is NULL, output empty string. Another words, I don't need the word "null" to be output to the user, just empty string. ...
2
votes
1answer
227 views

PostgreSQL WHERE clause with two OR'ed conditions, priority to first

I'm storing user data (username, email, password hash) in PostgreSQL, and I can only enforce uniqueness on username. I'd like to let users provide either their username or their email when they login. ...
0
votes
1answer
49 views

What is the correct way of filtering a property by multiple features?

Having the following tables: Property Feature PropertyHasFeature (property_id, feature_id) What is the right way to search properties by specifying multiple features? I want to list all ...
-1
votes
1answer
51 views

How to compare a result of a query to a number? [closed]

I have a query that return selects a table and returns one column with a number, and I want to know if the result is > 0. SELECT * FROM Table WHERE (SELECT amount from Table2) > 0 ...
1
vote
2answers
82 views

Not able to produce table based on conditional select

I would like to achieve something that probably ends up in some kind of conditional select (MS SQL) but I do not know how to. I have tried to simplified my problem to the description below: I have 3 ...
2
votes
1answer
225 views

Why should the most restrictive condition be listed last in the where clause?

The book I'm going through has given a rather poor explanation of why exactlt to place the most restrictive condition last in the WHERE clause. Say that we have Query 1: SELECT COUNT(*) FROM ...
4
votes
1answer
398 views

Search a Redis Database

Imagine having a tun of hashes in a Redis Database, each representing a user object. How would you get the user with for example the lowest registration date? The user where ts_registered is the ...
0
votes
1answer
40 views

Combine 2 SQL Queries

How do I combine these 2 queries? select a, b, c from MY_TABLE where date < sysdate+1 AND c is NULL order by id select a, b, c from MY_TABLE where date < sysdate AND b is NULL order by id
1
vote
1answer
742 views

Mysql update different fileds set depend on condition

I have two tables "a" : CREATE TABLE `a` ( `id` int(11) NOT NULL AUTO_INCREMENT, `i1` int(11) DEFAULT NULL, `i2` int(11) DEFAULT NULL, `ib` int(11) DEFAULT NULL, KEY `id` (`id`) ) ...
0
votes
2answers
217 views

How mysql process where condition

I have a query like Select * from tbl1 WHERE ( price > 10 AND qty > 200 AND condition=1 AND name like '%abc%') My question is how MySQL will process this? My concern is that I want ...
1
vote
2answers
1k views

Conditional WHERE clause

I have, from what I can tell, a unique question. I would like to know if there's a way to construct a query in which the existence of the actual where clause itself is conditional. I'm writing a ...
5
votes
1answer
4k views

How to export mysql database based on a where condition

I need to export the data and structure of a table but the data must have a specific condition (WHERE status=0 and id>20). How to export mysql database based on a where condition from phpMyAdmin or ...
2
votes
1answer
2k views

Can I mysqldump an entire database while using where='condition' on individual tables?

I have used mysqldump to dump an entire database, However, when I want to use --where=condition", on individual tables, I have dumped individual tables mysqldump --where='condition' mydb table ...
3
votes
4answers
4k views

MySQL : Conditional ORDER BY to only one column

Hello and thanks for taking time to read this question. I am using MySQL, and I want to sort results using ORDER BY to one specific column, but the results must be ordered according an specific ...
16
votes
4answers
37k views

Logical operators OR AND in condition and order of conditions in WHERE

Let's examine these two statements: IF (CONDITION 1) OR (CONDITION 2) ... IF (CONDITION 3) AND (CONDITION 4) ... If CONDITION 1 is TRUE, will CONDITION 2 be checked? If CONDITION 3 is FALSE, will ...