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')...
PL/SQL also has CASE expression which is similar to the CASE statement. A CASE expression evaluates a list of conditions and returns one of multiple possible result expressions. The result of a CASE expression is a single value whereas the result of a CASE statement is the execution of a se...
Evaluates a list of conditions and returns one of multiple possible result expressions. TheCASEexpression has two formats: The simpleCASEexpression compares an expression to a set of simple expressions to determine the result. The searchedCASEexpression evaluates a set of Boolean expressions to determin...
Evaluates a list of conditions and returns one of multiple possible result expressions. TheCASEexpression has two formats: The simpleCASEexpression compares an expression to a set of simple expressions to determine the result. The searchedCASEexpression evaluates a set of Boolean expressions to determin...
The CASE expression 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 the ELSE clause. ...
The function is modified by using the ALTER statement with the SCHEMABINDING option not specified. A function can be schema bound only if the following conditions are true: The function is a Transact-SQL function. The user-defined functions and views referenced by the function are also schema-bo...
A table can have multiple UNIQUE constraints. CLUSTERED | NONCLUSTERED Indicates that a clustered or a nonclustered index is created for the PRIMARY KEY or UNIQUE constraint. PRIMARY KEY constraints default to CLUSTERED, and UNIQUE constraints default to NONCLUSTERED. In a CREATE TABLE statement, ...
Oracle stops enforcing the constraint and removes it from the data dictionary. You can specify only one constraint for each drop_constraint_clause, but you can specify multiple drop_constraint_clauses in one statement. PRIMARY KEYSpecify PRIMARY KEY to drop the table's primary key constraint. ...