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Count the number of occurrences of a string in a VARCHAR field?
I have a table like this:
7 Answers
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How to change column datatype from character to numeric in PostgreSQL 8.4
...rom old to new type.
So this might work (depending on your data):
alter table presales alter column code type numeric(10,0) using code::numeric;
-- Or if you prefer standard casting...
alter table presales alter column code type numeric(10,0) using cast(code as numeric);
This will fail if you h...
python-pandas and databases like mysql
...pass@host:port/schema', echo=False)
f = pd.read_sql_query('SELECT * FROM mytable', engine, index_col = 'ID')
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Most efficient way to remove special characters from string
...ms.
The price to pay is, of course, the initialization of the huge lookup table and keeping it in memory. Well, it's not that much data, but it's much for such a trivial function...
private static bool[] _lookup;
static Program() {
_lookup = new bool[65536];
for (char c = '0'; c <= '9'; ...
What is the MySQL VARCHAR max size?
...QL has a maximum row size limit
The internal representation of a MySQL table has a maximum row size limit of 65,535 bytes, not counting BLOB and TEXT types. BLOB and TEXT columns only contribute 9 to 12 bytes toward the row size limit because their contents are stored separately from the rest of...
Database: To delete or not to delete records
...t possible of course) an aggregation scheme, and shove that off to another table. This will keep your primary table clean of 'deleted' data, as well as keep your secondary table optimized for monitoring purposes (or whatever you had in mind).
For temporal data, see: http://talentedmonkeys.wordpress...
Django: How to completely uninstall a Django app?
...dy management command that will give you the necessary SQL to drop all the tables for an app. See the sqlclear docs for more information. Basically, running ./manage.py sqlclear my_app_name gets you get the SQL statements that should be executed to get rid of all traces of the app in your DB. You st...
How to select multiple rows filled with constants?
Selecting constants without referring to a table is perfectly legal in an SQL statement:
15 Answers
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Vertical (rotated) text in HTML table
Is there a (portable) way to rotate text in a HTML table cell by 90°?
11 Answers
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Split function equivalent in T-SQL?
...to split '1,2,3,4,5,6,7,8,9,10,11,12,13,14,15...' (comma delimited) into a table or table variable.
15 Answers
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