CASE表达式是用来判断条件的,条件成立时返回某个值,条件不成立时返回另一个值。 语法: CASEWHENComparsionConditionTHENresultWHENComparsionConditionTHENresultELSEotherEND (注:各分支返回的数据类型需一致。) (注:when子句一定要有排他性,因为当when子句为真时,剩余的when子句会被忽略。) CASE表达式的用途: 1,转换...
SELECTcolumn1, column2, ...CASEWHENcondition1THENresult1WHENcondition2THENresult2-- Add more WHEN conditions and results as neededENDASalias_nameFROMtable_name; We can add as manyWHEN ... THENconditions as required in theCASEstatement. For example, -- multiple CASE conditions in SQLSELECTcusto...
b.STATUS, a.PAYMENTS_PENDING,CASEWHENc.PPAPPLSTRAT='Y'ANDa.PAYMENTS_PENDING='Y'ANDc.DAPPLSTRAT='Y'AND(b.PROBLEM_IDISNOTNULLANDb.STATUS<>'C')THEN'Y'WHENc.PPAPPLSTRAT='Y'ANDa.PAYMENTS_PENDING='Y'ANDc.CAPPLSTRAT='Y'AND(b.PROBLEM_IDISNULLOR(b.PROBLEM_IDISNOTNULLANDb.STATUS='C')...
The SQL IF statement is not a standard feature in all SQL databases. Its availability and syntax may vary between different database systems. Some databases use different conditional constructs like CASE WHEN. Popular database systems such as MySQL, PostgreSQL, and SQL Server have their own ways...
Returns the result_expression of the first input_expression = when_expression that evaluates to TRUE. Searched CASE expression Returns result_expression of the first Boolean_expression that evaluates to TRUE. Examples Using a SELECT statement with a simple CASE expression ...
Examples A. Use a SELECT statement with a simple CASE expression Within aSELECTstatement, a simpleCASEexpression allows for only an equality check; no other comparisons are made. The following example uses theCASEexpression to change the display of product line categories to make them more understa...
9、说明:创建视图:create view viewname as select statement 删除视图:drop view viewname 10、说明:几个简单的基本的sql语句 选择:select * from table1 where 范围 插入:insert into table1(field1,field2) values(value1,value2) 删除:delete from table1 where 范围更新:update table1 set field1=value...
Syntax for Transact-SQL multi-statement table-valued functions. syntaxsql 复制 CREATE [ OR ALTER ] FUNCTION [ schema_name. ] function_name ( [ { @parameter_name [ AS ] [ type_schema_name. ] parameter_data_type [ NULL ] [ = default ] [ READONLY ] } [ , ...n ] ] ) RETURNS...
You should only depend on order of evaluation of the WHEN conditions for scalar expressions (including non-correlated sub-queries that return scalars), not for aggregate expressions. Examples A. Using a SELECT statement with a simple CASE expression Within a SELECT statement, a simple CASE expressi...
SQL statements,OpenSearch:query clause The query clause is the most basic and indispensable part of a statement. The query clause defines the specific content to be queried based on a specific index field. You can specify mult...