Shulou(Shulou.com)06/01 Report--

# string concatenation concat (s1Powers2); concatenate the strings in last_name and first_name in the table

Select concat (last_name,first_name) as name from employees

# will only modify last_name, not first_name

SELECT first_name,last_name AS f FROM employees

# separate the two columns with commas and name them out_put

SELECT CONCAT (`last_ name`,',', `phone_ number`) AS out_put FROM employees

# ifnull determines whether it is empty, displays 0 instead of null if it is empty, and displays the column name as a result

SELECT IFNULL (commission_pct,0) AS result FROM employees

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