Why is the CASE Statement Important? The CASE WHEN statement is a valuable tool in SQL queries, offering several key benefits: Data transformation: enables you to create new columns based on the values of existing columns. Conditional aggregation: allows you to create aggregated values (e.g., ...
We can add as manyWHEN ... THENconditions as required in theCASEstatement. For example, -- multiple CASE conditions in SQLSELECTcustomer_id, first_name,CASEWHENcountry ='USA'THEN'United States of America'WHENcountry ='UK'THEN'United Kingdom'ENDAScountry_nameFROMCustomers; Run Code Here, the...
1topics: #CASE的两种基本用法2CASE OPERATOR3CASE STATEMENT45MariaDB [mysql]> helpcasestatement; #case的第一种用法6Name: 'CASE STATEMENT'7Description:8Syntax:9CASE case_value10WHEN when_value THEN statement_list11[WHEN when_value THEN statement_list] ...12[ELSE statement_list]13END CASE1415Or...
CASE selector WHEN selector_value_1 THEN statements_1 WHEN selector_value_1 THEN statement_2 ... ELSE else_statements END CASE; Code language: PostgreSQL SQL dialect and PL/pgSQL (pgsql) Let’s examine the syntax of the simple CASE statement in detail: 1) selector The selector is an...
...= "" IF ELSE 流程控制语句 在mysql存储过程中的用法: IF search_condition THEN statement_list [ELSEIF search_condition...[ELSE statement_list] END IF IF作为一条语句,在END IF后需要加上分号“;”以表示语句结束,其他语句如CASE、LOOP等也是相同的。...UPDATE salary SET sex = IF(sex = 'm'...
The following illustrates the syntax of the searched CASE statement: 1 2 3 4 5 6 CASE WHEN condition_1 THEN commands WHEN condition_2 THEN commands ... ELSE commands END CASE; MySQL evaluates each condition in the WHEN clause until it finds a condition whose value is TRUE , then corresp...
...= "" IF ELSE 流程控制语句 在mysql存储过程中的用法: IF search_condition THEN statement_list [ELSEIF search_condition...[ELSE statement_list] END IF IF作为一条语句,在END IF后需要加上分号“;”以表示语句结束,其他语句如CASE、LOOP等也是相同的。...= '' Swap Salary Leetcode中有一道题目就...
Adding aCASE STATEMENTpipeline step allows us to set the conditions for theWHENand theELSEjust like we did before, without having to type in the entire SQL syntax. Then after hiding the original ‘Provider’ column and using aREORDER COLUMNSstep and aPIVOT DATAstep we’ll get the same table...
The CASE statement cannot have an ELSE NULL clause, and it is terminated with END CASE instead of END. For the first syntax, case_value is an expression. This value is compared to the when_value expression in each WHEN clause until one of them is equal. When an equal when_value is ...
The SQL CASE Expression TheCASEexpression goes through conditions and returns a value when the first condition is met (like an if-then-else statement). So, once a condition is true, it will stop reading and return the result. If no conditions are true, it returns the value in theELSE...