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SQL Interview Success: Unlocking the Top 5 Frequently Asked Queries

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 Here are the five top commonly asked SQL queries in the interviews. These you can expect in Data Analyst, or, Data Engineer interviews. Top SQL Queries for Interviews 01. Joins The commonly asked question pertains to providing two tables, determining the number of rows that will return on various join types, and the resultant. Table1 -------- id ---- 1 1 2 3 Table2 -------- id ---- 1 3 1 NULL Output ------- Inner join --------------- 5 rows will return The result will be: =============== 1  1 1   1 1   1 1    1 3    3 02. Substring and Concat Here, we need to write an SQL query to make the upper case of the first letter and the small case of the remaining letter. Table1 ------ ename ===== raJu venKat kRIshna Solution: ========== SELECT CONCAT(UPPER(SUBSTRING(name, 1, 1)), LOWER(SUBSTRING(name, 2))) AS capitalized_name FROM Table1; 03. Case statement SQL Query ========= SELECT Code1, Code2,      CASE         WHEN Code1 = 'A' AND Code2 = 'AA' THEN "A" | "A

3 Best Methods to Read Files in Python

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Python supports three specific methods to read files- read, readline, readlines. All these you use on files. Each has its unique purpose. Below are the best examples. 3 Methods to read file read readline readlines Method-1: read It reads records from file in sequence. Here, file.txt is sample file with single row. file.txt abcdefghijk file_object.read(2) ==> you will get 'ab' file_object.read(4)  ===> you will get 'cdef' Here, the multiple read methods read the data in sequence. The read(x) method will read only the number of characters that mentioned in the read method. Again, if you give multiple read methods then it will read in sequence. Method-2: readline It reads the file line by line. Here, file.txt is a file with single row. file.txt abcdefghijk f ile_object.readline() ==> you will get ' abcdefghijk ' Here, it reads the file line by line. Method-3: readlines It reads all the records at a time. Here, file.txt is a file with two rows. file.txt ab