func convertIdentityToValue(n expr.Node) {
switch nt := n.(type) {
case *expr.BinaryNode:
switch rhn := nt.Args[1].(type) {
case *expr.IdentityNode:
rh2 := expr.NewStringNode(rhn.Text)
nt.Args[1] = rh2
}
}
}
// RewriteShowAsSelect Rewrite Schema SHOW Statements AS SELECT statements
// so we only need a Select Planner, not separate planner for show statements
func RewriteShowAsSelect(stmt *rel.SqlShow, ctx *Context) (*rel.SqlSelect, error) {
raw := strings.ToLower(stmt.Raw)
if ctx.Funcs == nil {
ctx.Funcs = fr
}
showType := strings.ToLower(stmt.ShowType)
//u.Debugf("showType=%q create=%q from=%q rewrite: %s", showType, stmt.CreateWhat, stmt.From, raw)
sqlStatement := ""
from := "tables"
if stmt.Db != "" {
from = fmt.Sprintf("%s.%s", stmt.Db, expr.IdentityMaybeQuote('`', from))
}
switch showType {
case "tables":
if stmt.Full {
// SHOW FULL TABLES; = select name, table_type from tables;
// TODO: note the stupid "_in_mysql", assuming i don't have to implement
/*
mysql> show full tables;
+---------------------------+------------+
| Tables_in_mysql | Table_type |
+---------------------------+------------+
| columns_priv | BASE TABLE |
*/
sqlStatement = fmt.Sprintf("select Table, Table_Type from %s;", from)
} else {
// show tables;
sqlStatement = fmt.Sprintf("select Table from %s;", from)
}
case "create":
// SHOW CREATE {TABLE | DATABASE | EVENT | VIEW }
switch strings.ToLower(stmt.CreateWhat) {
case "table":
sqlStatement = fmt.Sprintf("select Table , mysql_create as `Create Table` FROM `schema`.`%s`", from)
vn := expr.NewStringNode(stmt.Identity)
lh := expr.NewIdentityNodeVal("Table")
stmt.Where = expr.NewBinaryNode(lex.Token{T: lex.TokenEqual, V: "="}, lh, vn)
default:
return nil, fmt.Errorf("Unsupported show create %q", stmt.CreateWhat)
}
case "databases":
// SHOW databases; -> select Database from databases;
sqlStatement = "select Database from databases;"
case "columns":
if stmt.Full {
/*
mysql> show full columns from user;
+------------------------+-----------------------------------+-----------------+------+-----+-----------------------+-------+---------------------------------+---------+
| Field | Type | Collation | Null | Key | Default | Extra | Privileges | Comment |
*/
sqlStatement = fmt.Sprintf("select Field, typewriter(Type) AS Type, Collation, `Null`, Key, Default, Extra, Privileges, Comment from `schema`.`%s`;", stmt.Identity)
} else {
/*
mysql> show columns from user;
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
| Field | Type | Null | Key | Default | Extra |
+------------------------+-----------------------------------+------+-----+-----------------------+-------+
*/
sqlStatement = fmt.Sprintf("select Field, typewriter(Type) AS Type, `Null`, Key, Default, Extra from `schema`.`%s`;", stmt.Identity)
}
case "keys", "indexes", "index":
/*
mysql> show keys from user;
+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| user | 0 | PRIMARY | 1 | Host | A | NULL | NULL | NULL | | BTREE | | |
| user | 0 | PRIMARY | 2 | User | A | 7 | NULL | NULL | | BTREE | | |
+-------+------------+----------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
*/
sqlStatement = fmt.Sprintf("select Table, Non_unique, Key_name, Seq_in_index, Column_name, Collation, Cardinality, Sub_part, Packed, `Null`, Index_type, Index_comment from `schema`.`%s`;", stmt.Identity)
case "variables":
// SHOW [GLOBAL | SESSION] VARIABLES [like_or_where]
scope := stmt.Scope
if scope == "" {
scope = "session"
} else {
}
sqlStatement = fmt.Sprintf("select Variable_name, Value from `context`.`%s_variables`;", scope)
/*
mysql> show variables LIKE 'version';
+---------------+----------+
| Variable_name | Value |
+---------------+----------+
| version | 5.7.10-3 |
+---------------+----------+
*/
default:
u.Warnf("unhandled %s", raw)
return nil, fmt.Errorf("Unrecognized: %s", raw)
}
sel, err := rel.ParseSqlSelectResolver(sqlStatement, ctx.Funcs)
if err != nil {
return nil, err
}
sel.SetSystemQry()
if stmt.Like != nil {
// We are going to ReWrite LIKE clause to WHERE clause
sel.Where = &rel.SqlWhere{Expr: stmt.Like}
bn, ok := stmt.Like.(*expr.BinaryNode)
if ok {
rhn, ok := bn.Args[1].(*expr.StringNode)
// See if the Like Clause has wildcard matching, if so
// our internal vm uses * not %
if ok && rhn.Text == "%" {
rhn.Text = strings.Replace(rhn.Text, "%", "*", -1)
}
}
} else if stmt.Where != nil {
//u.Debugf("add where: %s", stmt.Where)
sel.Where = &rel.SqlWhere{Expr: stmt.Where}
}
if ctx.Schema == nil {
u.Warnf("missing schema for %s", stmt.Raw)
return nil, fmt.Errorf("Must have schema")
}
ctx.Schema = ctx.Schema.InfoSchema
if ctx.Schema == nil {
//u.Warnf("WAT? Still nil info schema?")
if ctx.Schema.InfoSchema == nil {
u.Warnf("WAT? info schema not self referencing?")
}
}
u.Debugf("SHOW rewrite: %q ==> %s", stmt.Raw, sel.String())
return sel, nil
}