SQL – CHECK Keyword
The CHECK keyword is a constraint that limits the value that can be placed in a column.
The CHECK keyword is a constraint that limits the value that can be placed in a column.
The CONSTRAINT keyword is used to create or delete a constraint from an existing table.
The DEFAULT keyword provides a default value for a column that will be added to all new records if no other value is specified.
The FOREIGN KEY keywords are a key (a field or fields in one table that refers to the PRIMARY KEY in another table) used to link two tables together.
Indexes are used to speed up the retrieval of data (searches/queries) from the database.
The LIMIT keyword is used to specify the number of records to return (MySQL).
The PRIMARY KEY keywords uniquely identifies each record in a table, which can have only one primary key consisting of a single field or multiple fields.
The TOP keyword is used to specify the number of records to return (SQL Server).
The UNIQUE keyword ensures that all values in a column are unique.
The MySQL ABS() function returns the absolute value of a number.
The MySQL ACOS() function returns the arc cosine of a number. The specified number must be between -1 and 1, or NULL will be returned.
The MySQL ADDDATE() function adds a time/date interval to a date and then returns the date.
The MySQL ADDTIME() function adds a time interval to a time/datetime and then returns the time/datetime.
The MySQL ASCII() function returns the ASCII value for the specific character.
The MySQL ASIN() function returns the arc sine of a number. The specified number must be between -1 and 1, or NULL will be returned.
The MySQL ATAN() function returns the arc tangent of one or two numbers.
The MySQL ATAN2() function returns the arc tangent of two numbers.
The MySQL AVG() function returns the average value of an expression (NULL values are ignored).
The MySQL BIN() function returns a binary representation of a number, as a string value.
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