How do write IF ELSE statement in a MySQL query
You probably want to use a CASE expression. They look like this: SELECT col1, col2, (case when (action = 2 and state = 0) THEN 1 ELSE 0 END) as state from tbl1;
if-statement
R – How to test for character(0) in IF statement
Use the identical function to check this. a <- character(0) identical(a, character(0)) # returns TRUE identical(a, “”) # returns FALSE identical(a, numeric(0)) # returns also FALSE
Is there a difference between “!=” and “is not” in C#?
Comparison table: Operator != is not Original purpose Value inequality Negated pattern matching Can perform value inequality Yes Yes Can perform negated pattern matching No Yes Can invoke implicit operator on left-hand operand Yes No Can invoke implicit operator on right-hand operand(s) Yes Yes1 Is its own operator Yes No2 Overloadable Yes No Since C# … Read more
Using the && operator in an if statement
So to make your expression work, changing && for -a will do the trick. It is correct like this: if [ -f $VAR1 ] && [ -f $VAR2 ] && [ -f $VAR3 ] then …. or like if [[ -f $VAR1 && -f $VAR2 && -f $VAR3 ]] then …. or even if [ … Read more
Performance difference between IIf() and If
VB has the following If statement which the question refers to, I think: ‘ Usage 1 Dim result = If(a > 5, “World”, “Hello”) ‘ Usage 2 Dim foo = If(result, “Alternative”) The first is basically C#’s ternary conditional operator and the second is its coalesce operator (return result unless it’s Nothing, in which case … Read more
When are square brackets required in a Bash if statement?
The square brackets are a synonym for the test command. An if statement checks the exit status of a command in order to decide which branch to take. grep -q “$text” is a command, but “$name” = ‘Bob’ is not–it’s just an expression. test is a command, which takes an expression and evaluates it: if … Read more
If conditions in a Makefile, inside a target
You can simply use shell commands. If you want to suppress echoing the output, use the “@” sign. For example: clean: @if [ “test” = “test” ]; then\ echo “Hello world”;\ fi Note that the closing ; and \ at each line are necessary (This is because make interpret each line as a seperate command … Read more
Difference between multiple if’s and elif’s?
Multiple if’s means your code would go and check all the if conditions, where as in case of elif, if one if condition satisfies it would not check other conditions..
if statements matching multiple values
How about: if (new[] {1, 2}.Contains(value)) It’s a hack though 🙂 Or if you don’t mind creating your own extension method, you can create the following: public static bool In<T>(this T obj, params T[] args) { return args.Contains(obj); } And you can use it like this: if (1.In(1, 2)) 🙂
Why does this if statement, with an assignment and equality check, evaluate to false?
The expression is not parsed the way you think. It’s not (test1=false) || (test1 == false) in which case the result would have been true, but test1 = (false || test1 == false) The value of false || test1 == false expression is computed first, and it is false, because test1 is set to true … Read more