sql cheat sheet
# Finding Data Queries # SELECT: used to select data from a database SELECT * FROM table_name; # DISTINCT: filters away duplicate values and returns rows of specified column SELECT DISTINCT column_name; # WHERE: used to filter records/rows SELECT column1, column2 FROM table_name WHERE condition; SELECT * FROM table_name WHERE condition1 AND condition2; SELECT * FROM table_name WHERE condition1 OR condition2; SELECT * FROM table_name WHERE NOT condition; SELECT * FROM table_name WHERE condition1 AND (condition2 OR condition3); SELECT * FROM table_name WHERE EXISTS (SELECT column_name FROM table_name WHERE condition); # ORDER BY: used to sort the result-set in ascending or descending order SELECT * FROM table_name ORDER BY column; SELECT * FROM table_name ORDER BY column DESC; SELECT * FROM table_name ORDER BY column1 ASC, column2 DESC; SELECT TOP: used to specify the number of records to return from top of table SELECT TOP number columns_names FROM table_name WHERE condition; SELECT TOP percent columns_names FROM table_name WHERE condition; # Not all database systems support SELECT TOP. The MySQL equivalent is the LIMIT clause SELECT column_names FROM table_name LIMIT offset, count; # LIKE: operator used in a WHERE clause to search for a specific pattern in a column # % (percent sign) is a wildcard character that represents zero, one, or multiple characters # _ (underscore) is a wildcard character that represents a single character SELECT column_names FROM table_name WHERE column_name LIKE pattern; LIKE ‘a%’ # (find any values that start with “a”) LIKE ‘%a’ # (find any values that end with “a”) LIKE ‘%or%’ # (find any values that have “or” in any position) LIKE ‘_r%’ # (find any values that have “r” in the second position) LIKE ‘a_%_%’ # (find any values that start with “a” and are at least 3 characters in length) LIKE ‘[a-c]%’ # (find any values starting with “a”, “b”, or “c” # See more in the source link