This question already has answers here:
Are table names in MySQL case sensitive?
(5 answers)
Delimiters in MySQL
(4 answers)
How can I see the specific value of the sql_mode?
(3 answers)
Closed 2 years ago.
What do the following three settings mean in MySQL Workbench?
These three parameters are mentioned briefly on the General Editor Settings, but I'm wondering what might be an example of their usage. For example:
SQL Identifiers are Case Sensitive: Enabled by default. Whether to treat identifiers separately if their names differ only in letter case.
Does this mean, for example that:
SELECT * from main_iteminstance
is different from:
SELECT * FROM main_iteminstance
The answer is no when I tried both, but isn't FROM a sql identifier, so what would this setting mean exactly?
This question already has answers here:
Unused Database Table Effects
(5 answers)
Closed 3 years ago.
I have a few temporary tables that I use for a second, then clear out the data. Should I delete these tables after I finish using them or would it be okay to leave them?
It is OK to leave them.
You may wish from time to time to check the file size and run a Compact & Repair.
This question already has answers here:
Transposing Dynamic Columns to Rows
(2 answers)
How can I return pivot table output in MySQL?
(10 answers)
Closed 5 years ago.
I have a storage application that stores data on change, about 200 columns with a time stamp and ID.
What I am trying to do is format each row into a table layout.
Raw data:
Here is how I would like to return the data:
I am new to MySQL so I apologize if this is an obvious answer, any help is appreciated!
This question already has answers here:
MySQL - Make an existing Field Unique
(7 answers)
Closed 9 years ago.
Is there anyway to make a column in mysql UNIQUE with out removing it and adding it again ?
I know how to add it but i would need to remove it first but i want to edit the current column and make it UNIQUE
I do
ALTER TABLE users
ADD UNIQUE (username)
But tells me that the column username is all ready there . When i want to edit it and not add it...
Could it be that the unique index is already there?
Could it be that there already are duplicates in that column?
Check MySQL - Make a Field Unique as it might fix your problem.
This question already has answers here:
remove all numeric characters from column mysql
(2 answers)
Closed 9 years ago.
I have millions of data in MySQL table, now I need to update one particular column of the table with only non-numeric characters. That is I need to remove all numbers from that column. The row wont be deleted, only updated with only non-numeric values.
I need some efficient way to achieve this.
Calling 10 times replace doesn't look good.
Thanks,
Ashish
For mysql, you just have to replace everything:
Replace(Replace(Replace(Replace(Replace(Replace(Replace(Replace(Replace(Replace(column,'9',''),'8',''),'7',''),'6',''),'5',''),'4',''),'3',''),'2',''),'1',''),'0','');