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Articles by George John
Page 62 of 79
How to count number of specific symbols in a row in MySQL?
You can use LENGTH() to count number of specific symbols in a row. Let us first create a table −mysql> create table DemoTable ( Value varchar(200) ); Query OK, 0 rows affected (0.54 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('?1234?6789?5656?324?'); Query OK, 1 row affected (0.17 sec)Following is the query to display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+----------------------+ | Value | +----------------------+ | ?1234?6789?5656?324? | ...
Read MoreHow to display the bit(1) fields in MySQL?
Let us first create a table. Here, our columns is of type bit(1) −mysql> create table DemoTable ( isCaptured bit(1) ); Query OK, 0 rows affected (1.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(0); Query OK, 1 row affected (0.26 sec) mysql> insert into DemoTable values(1); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable values(0); Query OK, 1 row affected (0.47 sec) mysql> insert into DemoTable values(1); Query OK, 1 row affected (0.29 sec)Following is the query to display all records from the table using select statement −mysql> select ...
Read MoreExtract the user ID from the username only in MySQL?
To extract the User ID only from MySQL, you can use SUBSTRING_INDEX(), which extracts the part of a string from the Username to get the User ID. Let us first display the user −mysql> SELECT USER();This will produce the following output −+----------------+ | USER() | +----------------+ | root@localhost | +----------------+ 1 row in set (0.00 sec)Let us now extract the UserID only −mysql> SELECT SUBSTRING_INDEX(USER(), '@', 1);This will produce the following output −+-------------------------------+ | SUBSTRING_INDEX(USER(), '@', 1) | +-------------------------------+ | root ...
Read MoreWhy does the order in which libraries are linked sometimes cause errors in GCC?
Basically this kind of errors are originated from the linker in the compilation phase. The default behavior of a linker is to take the code from archive libraries when the current program needs it.To work properly the libraries must be present in order. We can say that it must be there in the form “caller before callees”. This problem can be solved by choosing non-default behavior using flags, but in this process the linking may take larger time. Otherwise it can be solved by ordering the libraries correctly. Loaders and tsort these two can help to rearrange and correct the ...
Read MoreCreation of .ASM file using a text editor
The program written in assembly language is entered by us by the help of any editor, we prefer a screen editor because when we enter the program it is of no importance for the particular exact column label of instructions and the starting of the program. But the point to be noted that the instruction must start after column 1. More over the aligned program must be lucidly written for reading if its various fields should be assigned properly. There are many features which the editor provides like many help features which the user gets to be more familiar by ...
Read MoreHow to get the difference between two columns in a new column in MySQL?
Let us first create a table with columns for which we will calculate the difference in a new column −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, LowValue int, HighValue int ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(LowValue, HighValue) values(100, 200); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable(LowValue, HighValue) values(300, 700); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(LowValue, HighValue) values(1000, 2000); Query OK, 1 row affected (0.13 sec)Following is the query to ...
Read MoreHow to alter a MySQL Column from varchar(30) to varchar(100)?
You need to use ALTER TABLE command along with MODIFYThe syntax is as followsALTER TABLE yourTableName MODIFY COLUMN yourColumnName varchar(100) NOT NULL;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table syntaxOfAlterCommandDemo -> ( -> UserId int, -> UserName varchar(30), -> UserAge int, -> UserCityName varchar(50) -> ); Query OK, 0 rows affected (0.51 sec)Let us check the description of the table.The query is as followsmysql> desc syntaxOfAlterCommandDemo;The following is the output+--------------+-------------+------+-----+---------+-------+ | Field | Type ...
Read MoreReset_in* and Reset_out pins in 8085
Intel 8085 consists of a RESET_IN* pin which is an active low input pin. We RESET 8085 by placing a logic 0 on this pin at least for 0.5μs, after that the power is supplied to Vcc pin of 8085. Moreover, in practice we place the RESET_IN* in logic 0 state for a few milliseconds. A typical reset circuit which we use in ALS 8085 kit, is shown in the following Fig.The moment when the power supply is switched on, the Vcc pin gets +5V power here the RESET_IN* pin stays in logic 0 state for a time dependency on the ...
Read MoreChip Select Logic in 8085 Microprocessor
The master of microcomputer system is the microprocessor since all the operations of a computer are controlled by the microprocessor, the control unit often called as (CU) is found in the microprocessor. In the microcomputer system apart from processor there are several chips of RAM, CHIPS of EPROM and other Input Output port chips, timer 8253 is also present. But surprisingly at any moment of time the remains with only one of the chip. By activation of the chip selection the processor, the selection of the chip of the processor is done. Hence except the processor all chips must have ...
Read MoreTrap interrupt pin in 8085
A non-maskable interrupt is a Trap Interrupt which implies that whenever this pin gets activated, the 8085 always gets interrupted even if the state of 8085 is in DI. The input of Trap input is level sensitive and edge sensitive. Hence the Trap line always makes a transition from 0 to 1, and remains in state 1 until the end of the execution of an instruction for the interruption of 8085. A vectored-interrupt in 8085 is a TRAP. The starting address of 8085 is known by itself the of the ISS as 4.5 * 8 = 0024H. Hence we name the ...
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