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Select count(*) from multiple tables
How can I select count(*) from two different tables (call them tab1 and tab2 ) having as result:
18 Answers
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how to emulate “insert ignore” and “on duplicate key update” (sql merge) with postgresql?
...meant that you use a query like this: "start transaction; create temporary table temporary_table as select * from test where false; copy temporary_table from 'data_file.csv'; lock table test; update test set data=temporary_table.data from temporary_table where test.id=temporary_table.id; insert into...
Case insensitive searching in Oracle
...ur data to be the same case by using UPPER() or LOWER():
select * from my_table where upper(column_1) = upper('my_string');
or
select * from my_table where lower(column_1) = lower('my_string');
If column_1 is not indexed on upper(column_1) or lower(column_1), as appropriate, this may force a f...
Postgres manually alter sequence
... ALTER SEQUENCE [sequence] RESTART WITH (SELECT MAX(col) from table); does not work, whereas SELECT setval('sequence', (SELECT (MAX(col) from table), TRUE); does work. I get a syntax error. (Postgres 9.4)
– NuclearPeon
Jul 21 '18 at 1:35
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SQL Server Output Clause into a scalar variable
Is there any "simple" way to do this or I need to pass by a table variable with the "OUTPUT ... INTO" syntax?
3 Answers
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How to get size of mysql database?
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Run this query and you'll probably get what you're looking for:
SELECT table_schema "DB Name",
ROUND(SUM(data_length + index_length) / 1024 / 1024, 1) "DB Size in MB"
FROM information_schema.tables
GROUP BY table_schema;
This query comes from the mysql forums, where there are more c...
How to efficiently build a tree from a flat structure?
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Store IDs of the objects in a hash table mapping to the specific object. Enumerate through all the objects and find their parent if it exists and update its parent pointer accordingly.
class MyObject
{ // The actual object
public int ParentID { get; set; ...
Client-server synchronization pattern / algorithm?
...g every change (insert, update or delete) from any device into a "history" table. So if, for example, someone changes their phone number in the "contact" table, the system will edit the contact.phone field, and also add a history record with action=update, table=contact, field=phone, record=[contact...
How to add JTable in JPanel with null layout?
I want to add JTable into JPanel whose layout is null . JPanel contains other components. I have to add JTable at proper position.
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select count(*) from table of mysql in php
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here is the code for showing no of rows in the table with PHP
$sql="select count(*) as total from student_table";
$result=mysqli_query($con,$sql);
$data=mysqli_fetch_assoc($result);
echo $data['total'];
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