if case

DirectoryI. Condition selection: If statementTwo. Conditional judgment: Case statementThree. For loopI. Condition selection: If statement Single Branchif judgment condition; thenBranch code with true conditionFiExample: Judging whether a number

1. expr computes the integer variable valueS= ' Expr 2 + 3 'The arithmetic symbol and the parameter must have the space separate;2. Let command let s= (2+3) echo $s 3, for statement For variable in list

An If expression IF (EXPR1,EXPR2,EXPR3) If Expr1 is true (expr1 <> 0 and Expr1 <> NULL), then the return value of if () is expr2; Otherwise, the return value is EXPR3. The return value of IF () is a numeric value or a string value, depending on

MySQL can be used as an expression, or as a Process control statement in a stored procedure, as an expression:An If expressionIF(expr1,expr2,expr3)If Expr1 is true (expr1 <> 0 and Expr1 <> NULL), then the return value of if () is expr2; Otherwise

1. Logical judgment in shell scriptsFormat 1:if condition; then statement; FiFormat 2:if condition; then statement; Else statement; FiFormat 3:if ...; Elif ...; Then ...; else ...; FiLogical judgment expression:if [$a-gt $b], if [$a-lt 5], if [$b-eq

If condition test statement If-then-fiThe IF condition test statement runs the command after the if (judgment).If the exit status code for this command is 0, the command in the then section will be executed.If the exit status code for the

If, case, for, while, until, shellcase in Shell scripts If condition test statement If-then-fiIn the if condition test statement, the command following the if statement is run ).If the exit status code of the command is 0, the command in the then

Shell programming control structure: expr, let, for, while, until, shift, if, case, break, continue, function, select 1. expr calculates the integer variable value S = 'expr 2 + 3' The operator numbers and parameters must be separated by spaces; 2.

#!/bin/sh#--------------------------------------------------#Author: created by randolph  2016/10/21#blog:http://randolph.blog.51cto.com#function: this scripts function is   create|remove#version:4.1.2#------------------------------------------------

1. Conditional Select if statementSelect Execute:Single BranchIf judgment condition: ThenBranch code with true conditionFiDual Branchif judgment condition; ThenBranch code with true conditionElseThe condition is a false branch codeFiMulti-Branchif

1. Database design:For user-specific needs, then we create a most practical and high performance database!Steps for database design:01. Demand Analysis02. Conceptual Structure Design03. Logical Structure Design04. Physical Organization Design05.

In an SQL expression:An If expression:if (EXPR1,EXPR2,EXPR3)　　If Expr1 is true (expr1 <> 0 and Expr1 <> NULL), then the return value of if () is expr2; Otherwise the return value is EXPR3. The return value of IF () is a numeric value or a string

20.5 logical Judgments in shell scripts• format 1:if conditions; Then statement; FiExample: a=5If [$a-gt 3]; then echo OK; Fi[Email protected] shell]# sh If1.shok• format 2:if conditions; Then statement; else statement; FiExample: a=5If [$a-gt 3];

Logical judgments in shell scripts1.if then fi[[email protected] shell]# cat if1.sh#!/bin/basha=5if [ $a -gt 3 ]then echo okfi2.if then else fi:[email protected] shell]# sh -x if2.sh + a=1+ ‘[‘ 1 -gt 3 ‘]‘+ echo nooknook[[email protected]

DirectoryI. Condition selection: If statementTwo. Conditional judgment: Case statementThree. For loopI. Condition selection: If statement Single Branchif judgment condition; thenBranch code with true conditionFiExample: Judging whether a number

If syntax:if [expression]ThenCommandselif [Expression2]ThenCommandsElseCommandsFiCase Syntax: Case string1 inSTR1)commands;;STR2)commands;;*)Commans;;EsacLoop statement for syntax: for Var in listDoCommands done  In this form, for each item in the

1, write script/root/bin/createuser.sh, to achieve the following functions: Use a user name as a parameter, if the user specified parameter exists, it will show its existence, otherwise add, and generate a 8-bit random password and there is a file,

1.ifExpression: IF (Expr1, EXPR2, EXPR3)The EXPR1 condition is true, the value is Expr2, false, and the value is EXPR3Cases:SELECT o.id,u.account,catagory. ' Name ', Ordertime,detail.amount,periodtime, if (direction='0',' bullish ',' bearish ' = = =

"Conditional judgment"1. Judging by file type-B file to determine if the file exists and is a block device file (is a block device file is true)-c file to determine if the file exists and is a character device file (the character device file is true)

-- MySQL stored procedure/* Set @ result = 0; Create procedure login (-- defines parameters, including in, out, And inout types in user varchar (10 ), in pass varchar (10), out result INT) Begin declare passd varchar (10); -- declare declares