大约有 47,000 项符合查询结果（耗时：0.0371秒） [XML]
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
|
...
CSS3 selector :first-of-type with class name?
Is it possible to use the CSS3 selector :first-of-type to select the first element with a given class name? I haven't been successful with my test so I'm thinking it's not?
...
How to delete a row by reference in data.table?
...el.idxs' vs. 'keep.idxs'
keep.idxs <- setdiff(DT[, .I], del.idxs); # select row indexes to keep
cols = names(DT);
DT.subset <- data.table(DT[[1]][keep.idxs]); # this is the subsetted table
setnames(DT.subset, cols[1]);
for (col in cols[2:length(cols)]) {
DT.subset[, (col) := DT[...
How do I get currency exchange rates via an API such as Google Finance? [closed]
... require any kind of sign up.
[http://query.yahooapis.com/v1/public/yql?q=select * from yahoo.finance.xchange where pair in ("USDEUR", "USDJPY", "USDBGN", "USDCZK", "USDDKK", "USDGBP", "USDHUF", "USDLTL", "USDLVL", "USDPLN", "USDRON", "USDSEK", "USDCHF", "USDNOK", "USDHRK", "USDRUB", "USDTRY", "USD...
How to pick an image from gallery (SD Card) for my app?
...EQ_CODE_PICK_IMAGE:
if(resultCode == RESULT_OK){
Uri selectedImage = imageReturnedIntent.getData();
String[] filePathColumn = {MediaStore.Images.Media.DATA};
Cursor cursor = getContentResolver().query(
selectedImage, fileP...
How do I show an open file in eclipse Package Explorer?
...oices. The choices will vary depending on what plugins you have installed. Select the option you want and press Enter.
The fastest way to select an option is to use the first letter of the option, eg. to go to the Package Explorer, press P (you may have to do this 2 or 3 times depending on how many...
Is “else if” a single keyword?
...s section on keywords.
The grammar in section 6.4 also makes this clear:
selection-statement:
if ( condition ) statement
if ( condition ) statement else statement
The if in else if is a statement following the else term. The section also says:
[...]The substatement in a selection-statement...
Uniq by object attribute in Ruby
What's the most elegant way to select out objects in an array that are unique with respect to one or more attributes?
14 An...
Max return value if empty query
...oeSize = Workers.Where(x => x.CompanyId == 8)
.Select(x => x.ShoeSize)
.DefaultIfEmpty(0)
.Max();
The zero in DefaultIfEmpty is not necessary.
...
How to create relationships in MySQL
...s defined as the default storage engine,can check using command (mysql> SELECT @@default_storage_engine;)
– Arun
Feb 18 at 4:00
add a comment
|
...