What are basic techniques of indexing?

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What is error ora-12154: tns:could not resolve the connect identifier specified?

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What does cursor do in sql?

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How do we tune the code?

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Does sql use python?

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What is oracle ? why we should go for oracle database instead of diffrent databases available in the industry.

5 Answers   Polaris,

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What is the difference between delete, truncate and drop command?

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when a procedure /package is getting invalidated?

4 Answers   TCS,

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Hi All, I am new to both this blog and technology. I was able to see a response for one of the questions on triggers as below. I would like to know why are we using " if rtrim(to_char(sysdate,'day'))=rtrim('sunday') then" instead, can't we use " if sysdate = 'sunday' then". I can understand the use of "rtrim", but dont know y v r using to_char. I have seen this in many cases but did not get a convincible explaination. Please help me with this and do excuse if this question sounds silly. Thanks in advance...... create or replace trigger trg_sun before insert on <table name> begin if rtrim(to_char(sysdate,'day'))=rtrim('sunday') then raise_application_error(-20345,'no transaction in sunday'); end if; end trg_sun;

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SELECT emp_num, years, SUM(salary) FROM sales UNION ALL SELECT emp_id, SUM(takehomepay) FROM marketing What error is present in the sample code above? 1. Queries being combined with the UNION ALL statement are not allowed to have SELECT lists with a different number of expressions. 2. You are not allowed to use aggregate functions within two queries joined by a UNION ALL statement. 3. The UNION ALL statement incorrectly combines the "years" result from the first query with the "SUM (takehomepay)" result from the second query. 4. Unless the UNION ALL statement is replaced with a UNION statement, the queries will return duplicates. 5. The "emp_id" column from the second query must be renamed (or aliased) as "emp_num" so that it corresponds to the column name from the first query. Otherwise, the queries will not execute.

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what are the differences between char and varchar? : Sql dba

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How do I know if I have sql express or standard?

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