work until it is reactivated.
Este Cmap, tiene información relacionada con: DML, DELETE conditions If no condition is given then ALL rows are deleted BE CAREFUL, UPDATE syntax UPDATE <table> SET col1 = val1 [,col2 = val2...] [WHERE <condition>], FUNTIONS String CONCAT(expr1,expr2,...) Returns a concatenated string STRCMP(expr1,expr2) Compare two strings. CHAR(num1) Returns the character for each integer passed CHAR_LENGTH(str) Returns the length of the string str, measured in characters LOWER(str) Return the argument in lowercase UPPER(str) Return the argument in uppercase REVERSE(str) Reverse the characters in a string REPLACE(str,from_str,to_str) Returns the string str with all occurrences of the string from_str replaced by the string to_str. LOCATE(substr,str,pos) Returns the position of the first occurrence of substring substr in string str, starting at position pos. SUBSTRING(str,pos) Return a substring from string str starting at position pos, DELETE conditions Some versions of SQL also have TRUNCATE TABLE <T> which is like DELETE FROM <T> but it is quicker as it doesn’t record its actions, (NOT) IN See if a given value is in(or not in) a set of values Comparison Functions, SELECT [DISTINCT | ALL] <column-list> AS <column-name> FROM <table-names> <conditions> To FUNTIONS, ORDER BY Sorts the results of a query Syntax SELECT <columns> FROM <tables> ORDER BY <col> [ASCENDING | DESCENDING | ASC | DESC ], DELETE FROM <table> [WHERE <condition>] examples DELETE FROM Student WHERE Year = 2, Important to note the precedence of operators This precedence can be changed with the use of brackets () Operators +, -, /, *. DIV() Integer division % Returns the remainder of N divided by M, SELECT [DISTINCT | ALL] <column-list> AS <column-name> FROM <table-names> <conditions> Column Expression DISTINCT: Used to get non repeated data ALL: Default value. Show all data, UPDATE conditions All rows where the condition is true have the columns set to the given values, INSERT INTO <table> [col1, col2, ...] VALUES (val1, val2, ...) example INSERT INTO Student (Name, ID) VALUES (‘Mary’, 2), DML is A data manipulation language of SQL, (NOT) IN See if a given value is in(or not in) a set of values Syntax WHERE <value> IN|NOT IN <set>, SELECT can be displayed with DML, WHERE Indicates the condition or conditions that rows must satisfy to be selected and can include UNION statements and subqueries. you can use any of the functions and operators that MySQL supports, except for aggregate functions Syntax SELECT <column-list> FROM <table-names> [WHERE <condition>], Functions Boolean <condition>AND<condition> <condition>OR<condition>, FUNTIONS Agregation Aggregate functions compute summaries of data in a table COUNT The number of rows SUM The sum of the entries in a column AVG The average entry in a column MIN, MAX The minimum and maximum entries in a column, INSERT is for Add row(s) in a table, Important to note the precedence of operators This precedence can be changed with the use of brackets () Functions ROUND(X,D) Round the argument to D decimals (default is 0) TRUNCATE(X,D) Returns the number X, truncated to D decimal places (default is 0) POW(num) Return the argument raised to the specified power SQRT(num) Return the square root of the argument