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How do I check if a column is empty or null in MySQL?
...OR some_col = ' ' (one space inserted in the string) then it works on both MySQL and Oracle, see answer of "onedaywhen". some_col = '' doesn't work on Oracle as empty strings mean NULL there.
– Johanna
May 18 '15 at 14:07
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#1071 - Specified key was too long; max key length is 1000 bytes
...The INT(1) and INT(32) data types indicates another misunderstanding about MySQL. The numeric argument has no effect related to storage or the range of values allowed for the column. INT is always 4 bytes, and it always allows values from -2147483648 to 2147483647. The numeric argument is about p...
使用虚拟现实和App Inventor进行实验 · App Inventor 2 中文网
...Google 商店以查找各种 Cardboard 查看器，或在网上搜索有关如何制作自己的 Cardboard 查看器的提示。您还可以使用 Cardboard 以外的查看器。
Expeditions
Expeditions 演示显示沉浸式 360 度全景图。Google 于 2014 年在 Google I/O 2014 的主题演讲...
How to delete from multiple tables in MySQL?
...h out to an EXISTS in 99% of the cases and then there is the 1% where this MySQL syntax takes the day.
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What's the difference between VARCHAR and CHAR?
What's the difference between VARCHAR and CHAR in MySQL?
14 Answers
14
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MySQL ON vs USING?
In a MySQL JOIN , what is the difference between ON and USING() ? As far as I can tell, USING() is just more convenient syntax, whereas ON allows a little more flexibility when the column names are not identical. However, that difference is so minor, you'd think they'd just do away with USI...
How to declare a variable in MySQL?
How to declare a variable in mysql, so that my second query can use it?
7 Answers
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How can I suppress column header output for a single SQL statement?
I'm executing some SQL statements in batch (using the mysql command-line binary). I want one of my several SELECT statements to not print the column headers, just the selected records. Is this possible?
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MySQL “between” clause not inclusive?
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From the MySQL-manual:
This is equivalent to the expression
(min <= expr AND expr <= max)
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Best data type to store money values in MySQL
I want to store many records in a MySQL database. All of them contains money values. But I don't know how many digits will be inserted for each one.
Which data type do I have to use for this purpose?
VARCHAR or INT (or other numeric data types)?
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