CASE can be
used in any statement or clause that allows a valid expression
. For example, you can use CASE in statements such as SELECT, UPDATE, DELETE and SET, and in clauses such as select_list, IN, WHERE, ORDER BY, and HAVING.
Is it possible to use a case statement in a SQL FROM clause?
No, you can’t pick a table to query using a CASE statement.
CASE statements only go within expressions
, such as for a column’s value or as part of your WHERE expression.
Can we use or condition in WHERE clause in SQL?
The WHERE condition in SQL can be used in conjunction with
logical operators such as AND and OR
, comparison operators such as ,= etc.
Can we use decode in WHERE clause?
And Decode works in a similar fashion, although I think it’s less readable. SELECT (columns list) FROM AGREEMENT A WHERE A. ACCOUNT = 545 AND A. GRP_ID = DECODE(?, 0, A.
Can I use CASE statement in WHERE clause in Oracle?
Introduction to Oracle CASE expression
You can use a CASE expression
in any statement or clause that accepts a valid expression
. For example, you can use the CASE expression in statements such as SELECT , UPDATE , or DELETE , and in clauses like SELECT , WHERE , HAVING , and ORDDER BY .
Can we use 2 WHERE clause in SQL?
Example – Two Conditions in the WHERE Clause (OR Condition)
You can use the OR condition in the WHERE clause
to test multiple conditions where the record is returned if any one of the conditions are
met.
Does DML use WHERE clause in its statement?
Basic command present in DDL are CREATE, DROP, RENAME, ALTER etc. BASIC command present in DML are UPDATE, INSERT, MERGE etc. DDL does not use WHERE clause in its statement. While
DML uses WHERE clause
in its statement.
What is difference between WHERE and HAVING clause in SQL?
WHERE
Clause is used to filter the records from the table based on the specified condition
. … HAVING Clause is used to filter record from the groups based on the specified condition.
How do I use decode?
The DECODE function returns a value that is the same datatype as the
first result
in the list. If the first result is NULL, then the return value is converted to VARCHAR2. If the first result has a datatype of CHAR, then the return value is converted to VARCHAR2. If no matches are found, the default value is returned.
What is the difference between decode and case?
CASE is a statement while DECODE is a function. CASE can work with logical operators other than ‘=’ : DECODE performs an equality check only. CASE is capable of
other logical comparisons such as < ,>
,BETWEEN , LIKE etc.
Are Named blocks and are stored in the database?
A named block is
stored into the Oracle Database server
and can be reused later. A block without a name is an anonymous block. An anonymous block is not saved in the Oracle Database server, so it is just for one-time use. However, PL/SQL anonymous blocks can be useful for testing purposes.
Can case statement return multiple values in Oracle?
4 Answers. A
CASE statement cannot return more than one value
, it is a function working on one value.
Are Oracle cases insensitive?
By default, Oracle identifiers (table names, column names, etc.)
are case-insensitive
. You can make them case-sensitive by using quotes around them (eg: SELECT * FROM “My_Table” WHERE “my_field” = 1 ).
How does case work in Oracle?
In a simple CASE expression, Oracle Database
searches for the first WHEN
… THEN pair for which expr is equal to comparison_expr and returns return_expr . If none of the WHEN … THEN pairs meet this condition, and an ELSE clause exists, then Oracle returns else_expr .
Can you have multiple WHERE clauses in SQL?
You
can specify multiple conditions in a single
WHERE clause to, say, retrieve rows based on the values in multiple columns. You can use the AND and OR operators to combine two or more conditions into a compound condition. AND, OR, and a third operator, NOT, are logical operators.
How do I combine two conditions in SQL?
The SQL AND condition and OR condition can be combined to test for multiple conditions in a SELECT, INSERT, UPDATE, or DELETE statement. When combining these conditions, it is important to use
parentheses
so that the database knows what order to evaluate each condition.
