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What is the “N+1 selects problem” in ORM (Object-Relational Mapping)?
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SELECT
table1.*
, table2.*
INNER JOIN table2 ON table2.SomeFkId = table1.SomeId
That gets you a result set where child rows in table2 cause duplication by returning the table1 results for each child row in table2. O/R mappers sho...
Alternate table row color using CSS?
I am using a table with alternate row color with this.
9 Answers
9
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How to filter SQL results in a has-many-through relation
Assuming I have the tables student , club , and student_club :
13 Answers
13
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SQL “select where not in subquery” returns no results
... query:
LEFT JOIN / IS NULL:
SELECT *
FROM common
LEFT JOIN
table1 t1
ON t1.common_id = common.common_id
WHERE t1.common_id IS NULL
NOT EXISTS:
SELECT *
FROM common
WHERE NOT EXISTS
(
SELECT NULL
FROM table1 t1
WHERE t1.common_id = ...
Why would someone use WHERE 1=1 AND in a SQL clause?
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Indirectly Relevant: when 1=2 is used:
CREATE TABLE New_table_name
as
select *
FROM Old_table_name
WHERE 1 = 2;
this will create a new table with same schema as old table. (Very handy if you want to load some data for compares)
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How to wrap text using CSS? [duplicate]
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Try doing this. Works for IE8, FF3.6, Chrome
<body>
<table>
<tr>
<td>
<div style="word-wrap: break-word; width: 100px">gdfggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg...
How to prevent line-break in a column of a table cell (not a single cell)?
How can I prevent automatic line breaks in a column of table (not a single cell)?
9 Answers
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There can be only one auto column
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My MySQL says "Incorrect table definition; there can be only one auto column and it must be defined as a key" So when I added primary key as below it started working:
CREATE TABLE book (
id INT AUTO_INCREMENT NOT NULL,
accepted_terms BIT(1) NO...
MySQL Error 1093 - Can't specify target table for update in FROM clause
I have a table story_category in my database with corrupt entries. The next query returns the corrupt entries:
16 Answers...
How to update Identity Column in SQL Server?
...because it started
with a big number 10010 and it's related with another table, now I have 200 records and I want to fix this issue before the records increases.
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