大约有 47,000 项符合查询结果（耗时：0.0345秒） [XML]
What's faster, SELECT DISTINCT or GROUP BY in MySQL?
...'t, then use DISTINCT.
GROUP BY in MySQL sorts results. You can even do:
SELECT u.profession FROM users u GROUP BY u.profession DESC
and get your professions sorted in DESC order.
DISTINCT creates a temporary table and uses it for storing duplicates. GROUP BY does the same, but sortes the disti...
MySQL “NOT IN” query
...
To use IN, you must have a set, use this syntax instead:
SELECT * FROM Table1 WHERE Table1.principal NOT IN (SELECT principal FROM table2)
share
|
improve this answer
|
...
SELECT INTO using Oracle
I'm trying to do a SELECT INTO using Oracle. My query is:
3 Answers
3
...
UITableview: How to Disable Selection for Some Rows but Not Others
... able to click it at all) The table contains two groups. I want to disable selection for the first group only but not the second group. Clicking the first row of second group navigates to my tube player view .
...
In MySQL, how to copy the content of one table to another table within the same database?
...
INSERT INTO TARGET_TABLE SELECT * FROM SOURCE_TABLE;
EDIT: or if the tables have different structures you can also:
INSERT INTO TARGET_TABLE (`col1`,`col2`) SELECT `col1`,`col2` FROM SOURCE_TABLE;
EDIT: to constrain this..
INSERT INTO TARGET_TAB...
HTML Form: Select-Option vs Datalist-Option
I was wondering what the differences are between Select-Option and Datalist-Option. Is there any situation in which it would be better to use one or the other? An example of each follows:
...
Entity Framework select distinct name
...
Using lambda expression..
var result = EFContext.TestAddresses.Select(m => m.Name).Distinct();
share
|
improve this answer
|
follow
|
...
How do I check if a column is empty or null in MySQL?
...
This will select all rows where some_col is NULL or '' (empty string)
SELECT * FROM table WHERE some_col IS NULL OR some_col = '';
share
|
...
How do I split a string so I can access item x?
...0,
PATINDEX('%|%', @products))
SELECT @individual
SET @products = SUBSTRING(@products,
LEN(@individual + '|') + 1,
LEN(@products))
END
ELSE
BEGIN
SET @individu...
How to copy data from one table to another new table in MySQL?
...hat you want:
INSERT INTO table2 (st_id,uid,changed,status,assign_status)
SELECT st_id,from_uid,now(),'Pending','Assigned'
FROM table1
If you want to include all rows from table1. Otherwise you can add a WHERE statement to the end if you want to add only a subset of table1.
I hope this helps.
...