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MySQL ON DUPLICATE KEY UPDATE for multiple rows insert in single query
I have a SQL query where I want to insert multiple rows in single query. so I used something like:
3 Answers
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Select where count of one field is greater than one
...uld be a GROUP BY defined for proper valuation in the HAVING clause, but MySQL does allow hidden columns from the GROUP BY...
Is this in preparation for a unique constraint on someField? Looks like it should be...
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What is a None value?
...as called with an argument or not.
Other languages have similar concepts. SQL has NULL; JavaScript has undefined and null, etc.
Note that in Python, variables exist by virtue of being used. You don't need to declare a variable first, so there are no really empty variables in Python. Setting a vari...
Why should I use document based database instead of relational database?
... aren't simply accessed via REST services, but require a much more complex SQL API. Often these API's (JDBC, ODBC, etc.) are quite complex. REST is quite simple.
Ad-hoc and schema-free with a flat address space. Relational databases have complex, fixed schema. You define tables, columns, indexes...
Repair all tables in one go
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from command line you can use:
mysqlcheck -A --auto-repair
http://dev.mysql.com/doc/refman/5.0/en/mysqlcheck.html
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MYSQL Dump only certain rows
I am trying to do a mysql dump of a few rows in my database. I can then use the dump to upload those few rows into another database. The code I have is working, but it dumps everything. How can I get mysqldump to only dump certain rows of a table?
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How to search a specific value in all tables (PostgreSQL)?
...e to search every column of every table for a particular value in PostgreSQL?
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must appear in the GROUP BY clause or be used in an aggregate function
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Yes, this is a common aggregation problem. Before SQL3 (1999), the selected fields must appear in the GROUP BY clause[*].
To workaround this issue, you must calculate the aggregate in a sub-query and then join it with itself to get the additional columns you'd need to show...
Get table names using SELECT statement in MySQL
In MySQL, I know I can list the tables in a database with:
12 Answers
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SELECT DISTINCT on one column
Using SQL Server, I have...
7 Answers
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