oracle 在 case 语句中返回一个布尔值
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Returning a boolean value in a case statement
提问by M.K.
I am trying to return a boolean value from a case statement but the compiler is complaining about a ORA-00936: missing expression error:
我试图从 case 语句返回一个布尔值，但编译器抱怨 ORA-00936: missing expression 错误：
SELECT
CASE MYCOLUMN
WHEN NULL THEN true
ELSE
false
END,
FROM MYTABLE;
I also tried the following but it doesn't work:
我也尝试了以下但它不起作用：
SELECT
CASE MYCOLUMN
WHEN NULL THEN SELECT true
ELSE
SELECT false
END,
FROM MYTABLE;
Is it possible to do this?
是否有可能做到这一点？
回答by juergen d
You need the ISoperator for NULLchecks
您需要IS操作员进行NULL检查
SELECT CASE WHEN MYCOLUMN IS NULL
THEN 1
ELSE 0
END
FROM MYTABLE;
回答by Rusty
BOOLEANtype is not supported in SQL. It is supported only in procedural PL/SQL
BOOLEANSQL 中不支持类型。它仅在过程 PL/SQL 中受支持
