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I'm creating a stored procedure to return search results where some of the parameters are optional. In PL/SQL if we write select statement with INTO clause it may return two exceptions NO_DATA_FOUND or TOO_MANY_ROW. I want an "if statement" in my where clause but can't get it working. The where clause should filter by only the non-null parameters. How to check the Average sequential Read time by STAT and STAD.
IF statements can be used to conditionally enter into some logic based on the status of a condition being satisfied. SQL Server provides a mechanism for returning different values in a SELECT clause based on Boolean conditions. The IF statement is logically equivalent to a CASE statements with a searched-case-statement-when clause. The IF statement supports the use of optional ELSE IF clauses and a default ELSE clause. An END IF clause is required to indicate the end of the statement.
Just so you understand, IF is procedural code in T-SQl. It canot be used in an insert/update/delete/select statement it can only be used to determine which of two statements you want to run. you can handle Too_Many_Rows exception when you are writing into a PL/SQL block SELECT...INTO statement.
SQL Server compares this value to the expression and when the values match, it returns the THEN clauses [return value]. A big problem arises though when you want to optionally filter for a column that is also nullable... if the data in the column is null for a given row If none of the WHEN clauses equates to true, SQL Server returns the [return value] in the optional ELSE clause. If the ELSE clause is omitted and no value is matched, NULL is returned. One downside of If statements is that if there are a number of different actions that must be taken based on some variable value, the number of If statements can explode, leading to bloated, unreadable code.