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Using DISTINCT and COUNT together in a MySQL Query
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use
SELECT COUNT(DISTINCT productId) from table_name WHERE keyword='$keyword'
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Condition within JOIN or WHERE
...in join improve performance for large amount of data with properly indexed tables.
– Shahdat
Oct 6 '16 at 15:13
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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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How do I show the schema of a table in a MySQL database?
From the MySQL console, what command displays the schema of any given table?
5 Answers
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How to calculate moving average using NumPy?
...inciple behind this answer is widely used in image processing (summed area tables they call it), so the issue had to be in the implementation. A good example of being bit by premature optimization, since I kind of recall doing the operation in-place "because it will be more efficient." On the bright...
What is the difference between vmalloc and kmalloc?
...ral virtual-to-physical address mappings will have to be added to the page table. And in the worst case, there will be (size of buffer/page size) number of mappings added to the page table.
This also adds pressure on TLB (the cache entries storing recent virtual to physical address mappings) when a...
CSS Printing: Avoiding cut-in-half DIVs between pages?
... only way I could get this to work for IE was to wrap each div in it's own table and set the page-break-inside on the table to avoid.
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Center image in div horizontally [duplicate]
...x solid #888;
width: 100px;
height: 100px;
}
.inner
{
display:table-cell;
height: 100px;
width: 100px;
vertical-align: middle;
}
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How can an html element fill out 100% of the remaining screen height, using css only?
... is where magic comes into picture - since we have 'min-height' on playing table, we are telling browser that <body> is superior over <html> because <body> holds the min-height. This in turn, allows <body> to override <html> because <html> had height already earli...
MySQL “Group By” and “Order By”
I want to be able to select a bunch of rows from a table of e-mails and group them by the from sender. My query looks like this:
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