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MySQLi Articles
Page 328 of 341
Resolve usage of quotes ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use?
In MySQL, you can use two different types of quotation marks which is backtick and another is single quotes or double quotes. In this case, maybe you are using single quotes to the column name that’s why you are getting error. You need to use the backtick symbol (` `) instead of single quotes. Backtick can be used with column names while single quotes can be used for strings.To understand the above error, let us create a table. The query to create a table is as follows −mysql> create table Backtick_SymbolDemo -> ( -> Id int NOT NULL ...
Read MoreMySQL “not a variable or NEW pseudo-variable” message. What is this error in my Stored Procedure?
To get rid of this error message, let us see a sample example. But before that let us go through the concept to fix it.Use variable to get the value from stored procedure. The variable will prefix with @ symbol. The syntax is as follows −CALL yourStoredProcedureName(yourParameter1, yourParameter2, ..........N, @yourVariableName);To see the value of variable you need to use select statement. The syntax is as follows −SELECT @yourVariableName;To understand the above syntax, let us create a table and insert some records in the table.The query to create a table is as follows −mysql> create table StoredProcedureDemo -> ( ...
Read MoreCreate MySQL column with Key=MUL?
You need to use ADD KEY to make a column with Key=MUL. The syntax is as follows −ALTER TABLE yourTableName MODIFY COLUMN yourColumnName data type, ADD KEY(yourColumnName);To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table Instructor -> ( -> Instructor_Id int, -> Instructor_Name varchar(30), -> Instructor_CourseName varchar(100) -> ); Query OK, 0 rows affected (0.63 sec)Now you can look the table description of the table, the column KEY does not have any MUL key. The query is as follows to check the ...
Read MoreMySQL CREATE USER with a variable?
You can use a dynamic query for this. First set the variable name for username and variable name for a password. The syntax is as follows −SET @anyVariableName=’yourUserName’; SET @anyVariableName1=’yourpassword’;Now you can use the CONCAT() function from MySQL. The syntax is as follows −SET @yourQueryName = CONCAT (' CREATE USER "', @anyVariableName, '"@"localhost" IDENTIFIED BY "', @anyVariableName1, '" ' );Let us use the prepared statement PREPARE. The syntax is as follows −PREPARE yourStatementVariableName FROM @yourQueryName;Now you can execute the statement. The syntax is as follows −EXECUTE yourStatementVariableName;Deallocate the above using the DEALLOCATE PREPARE. The syntax is as follows −DEALLOCATE ...
Read MoreHow to DROP a database in MySQL with character '?' in its name?
To drop a database with the character ‘?’ in its name, you need to use backtick symbol around the database name. The syntax is as follows −DROP DATABASE `yourDatabaseName`;To understand the above syntax, let us create a database. The query to create a database is as follows −mysql> create database `test?data`; Query OK, 1 row affected (0.14 sec)So, I have a database with? character. The query to show all databases is as follows −mysql> show databases;The following is the output −+-----------------------+ | Database | +-----------------------+ | business | ...
Read MoreMySQL: delete all rows containing string “foo” in sample table “bar”?
To delete all rows containing string “foo” in table “bar”, you need to use LIKE operator.To understand the above syntax, let us create a sample table with name “bar”. The query to create a table is as follows. We will always insert records with string “foo” using INSERT command after creating the below table −mysql> create table bar -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Words longtext, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.61 sec)Now you can insert some records in the table using insert command. The string “foo” ...
Read MoreWhy is “LIMIT 0” even allowed in MySQL SELECT statements?
As you know if you use LIMIT 0 in MySQL SELECT statement, it returns an empty set.The LIMIT can be used when you want a specified number of rows from a result rather than the entire rows. If you use any MySQL API, then the job of LIMIT is to acquire the type of result columns.LIMIT 0 can be used to check the validity of a query. For more details use the following link −https://dev.mysql.com/doc/refman/8.0/en/limit-optimization.htmlHere is the demo of LIMIT 0. The query to create a table is as follows −mysql> create table Limit0Demo -> ( -> Id ...
Read MoreREGEX Match integers 6 through 10 in MySQL?
Here you can use BETWEEN operator. The syntax is as follows −SELECT *FROM yourTableName WHERE yourColumnName BETWEEN 6 AND 10;You can use regular expression like this. The syntax is as follows −SELECT *FROM yourTableName WHERE yourColumnName REGEXP '10|[6-9]';To understand the both syntax, let us create a table. The query to create a table is as follows −mysql> create table RegularExpressionDemo -> ( -> Id int -> ); Query OK, 0 rows affected (1.11 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into RegularExpressionDemo values(1); Query OK, ...
Read MoreMySQL update query to remove spaces?
You can use TRIM() function to remove spaces. The syntax is as follows −UPDATE yourTableName SET yourColumnName=TRIM(yourColumnName);To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table removeSpaceDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> UserId varchar(20), -> UserName varchar(10), -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.81 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into removeSpaceDemo(UserId, ...
Read MoreRemove first two characters of all fields in MySQL?
To remove the first two characters of all fields, you need to use SUBSTRING() function from MySQL. The syntax is as follows −UPDATE yourTableName SET yourColumnName=SUBSTRING(yourColumnName, 3) WHERE yourCondition;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table RemoveFirstTwoCharacterDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> StringValue varchar(30), -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (1.04 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into RemoveFirstTwoCharacterDemo(StringValue) values('U:100'); Query OK, 1 ...
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